cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A049085 Irregular table T(n,k) = maximal part of the k-th partition of n, when listed in Abramowitz-Stegun order (as in A036043).

Original entry on oeis.org

0, 1, 2, 1, 3, 2, 1, 4, 3, 2, 2, 1, 5, 4, 3, 3, 2, 2, 1, 6, 5, 4, 3, 4, 3, 2, 3, 2, 2, 1, 7, 6, 5, 4, 5, 4, 3, 3, 4, 3, 2, 3, 2, 2, 1, 8, 7, 6, 5, 4, 6, 5, 4, 4, 3, 5, 4, 3, 3, 2, 4, 3, 2, 3, 2, 2, 1, 9, 8, 7, 6, 5, 7, 6, 5, 4, 5, 4, 3, 6, 5, 4, 4, 3, 3, 5, 4, 3, 3, 2, 4, 3, 2, 3, 2, 2, 1, 10, 9, 8, 7, 6, 5, 8, 7, 6
Offset: 0

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Author

Keywords

Comments

a(0) = 0 by convention. - Franklin T. Adams-Watters, Jun 24 2014
Like A036043 this is important for calculating sequences defined over the numeric partitions, cf. A000041. For example, the triangular array A019575 can be calculated using A036042 and this sequence.
The row sums are A006128. - Johannes W. Meijer, Jun 21 2010
The name is correct if the partitions are read in reverse, so that the parts are weakly increasing. The version for non-reversed partitions is A334441. - Gus Wiseman, May 21 2020

Examples

			Rows:
  [0];
  [1];
  [2,1];
  [3,2,1];
  [4,3,2,2,1];
  [5,4,3,3,2,2,1];
  ...
		

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 831.

Crossrefs

Row lengths are A000041.
Row sums are A006128.
The length of the partition is A036043.
The number of distinct elements of the partition is A103921.
The Heinz number of the partition is A185974.
The version ignoring length is A194546.
The version for non-reversed partitions is A334441.
Lexicographically ordered reversed partitions are A026791.
Reversed partitions in Abramowitz-Stegun order are A036036.
Reverse-lexicographically ordered partitions are A080577.
Partitions in Abramowitz-Stegun order are A334301.

Programs

  • Maple
    with(combinat):
    nmax:=9:
    for n from 1 to nmax do
       y(n):=numbpart(n):
       P(n):=partition(n):
       for k from 1 to y(n) do
          B(k):=P(n)[k]
       od:
       for k from 1 to y(n) do
          s:=0: j:=0:
          while sJohannes W. Meijer, Jun 21 2010
  • Mathematica
    Table[If[n==0,{0},Max/@Sort[Reverse/@IntegerPartitions[n]]],{n,0,8}] (* Gus Wiseman, May 21 2020 *)
  • PARI
    A049085(n,k)=if(n,partitions(n)[k][1],0) \\ M. F. Hasler, Jun 06 2018

Extensions

More terms from Wolfdieter Lang, Apr 28 2005
a(0) inserted by Franklin T. Adams-Watters, Jun 24 2014

A115623 Irregular triangle read by rows: row n lists numbers of distinct parts of partitions of n in Mathematica order.

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 1, 1, 2, 1, 2, 1, 1, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 1, 3, 2, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 3, 2, 1, 3, 2, 3, 2, 2, 2, 3, 3, 2, 1, 2, 2, 2, 1, 1, 2, 2, 2, 2, 3, 2, 2, 3, 2, 3, 2, 2, 3, 3, 3, 3, 2, 1, 3, 2, 2, 3, 3, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 3, 2, 2
Offset: 0

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Author

Keywords

Comments

The row length sequence of this table is p(n)=A000041(n) (number of partitions).
In order to count distinct parts of a partition consider the partition as a set instead of a multiset. E.g., n=6: read [3,1,1,1] as {1,3} and count the elements, here 2.
Rows are the same as the rows of A103921, but in reverse order.

Examples

			Triangle starts:
0
1
1, 1
1, 2, 1
1, 2, 1, 2, 1
1, 2, 2, 2, 2, 2, 1
1, 2, 2, 2, 1, 3, 2, 1, 2, 2, 1
1, 2, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 2, 2, 1
1, 2, 2, 2, 2, 3, 2, 1, 3, 2, 3, 2, 2, 2, 3, 3, 2, 1, 2, 2, 2, 1
1, 2, 2, 2, 2, 3, 2, 2, ...
a(5,4)=2 from the fourth partition of 5 in the mentioned order, i.e., [3,1^2], which has two distinct parts, namely 1 and 3.
		

Crossrefs

Programs

  • Mathematica
    Table[Length /@ Union /@ IntegerPartitions[n], {n, 0, 8}] // Flatten  (* Robert Price, Jun 11 2020 *)

Formula

a(n, m) = number of distinct parts of the m-th partition of n in Mathematica order; n >= 0, m = 1..p(n) = A000041(n).

Extensions

Edited and corrected by Franklin T. Adams-Watters, May 29 2006

A334441 Maximum part of the n-th integer partition in Abramowitz-Stegun (sum/length/lex) order; a(0) = 0.

Original entry on oeis.org

0, 1, 2, 1, 3, 2, 1, 4, 2, 3, 2, 1, 5, 3, 4, 2, 3, 2, 1, 6, 3, 4, 5, 2, 3, 4, 2, 3, 2, 1, 7, 4, 5, 6, 3, 3, 4, 5, 2, 3, 4, 2, 3, 2, 1, 8, 4, 5, 6, 7, 3, 4, 4, 5, 6, 2, 3, 3, 4, 5, 2, 3, 4, 2, 3, 2, 1, 9, 5, 6, 7, 8, 3, 4, 4, 5, 5, 6, 7, 3, 3, 4, 4, 5, 6, 2, 3, 3
Offset: 0

Views

Author

Gus Wiseman, May 06 2020

Keywords

Comments

First differs from A049085 at a(8) = 2, A049085(8) = 3.
The parts of a partition are read in the usual (weakly decreasing) order. The version for reversed (weakly increasing) partitions is A049085.

Examples

			Triangle begins:
  0
  1
  2 1
  3 2 1
  4 2 3 2 1
  5 3 4 2 3 2 1
  6 3 4 5 2 3 4 2 3 2 1
  7 4 5 6 3 3 4 5 2 3 4 2 3 2 1
  8 4 5 6 7 3 4 4 5 6 2 3 3 4 5 2 3 4 2 3 2 1
		

Crossrefs

Row lengths are A000041.
The length of the same partition is A036043.
Ignoring partition length (sum/lex) gives A036043 also.
The version for reversed partitions is A049085.
a(n) is the maximum element in row n of A334301.
The number of distinct parts in the same partition is A334440.
Lexicographically ordered reversed partitions are A026791.
Reversed partitions in Abramowitz-Stegun (sum/length/lex) order are A036036.
Partitions in increasing-length colex order (sum/length/colex) are A036037.
Graded reverse-lexicographically ordered partitions are A080577.
Partitions counted by sum and number of distinct parts are A116608.
Graded lexicographically ordered partitions are A193073.
Partitions in colexicographic order (sum/colex) are A211992.
Partitions in dual Abramowitz-Stegun (sum/length/revlex) order are A334439.

Programs

  • Mathematica
    Table[If[n==0,{0},Max/@Sort[IntegerPartitions[n]]],{n,0,10}]

A115621 Signature of partitions in Abramowitz and Stegun order.

Original entry on oeis.org

1, 1, 2, 1, 1, 1, 3, 1, 1, 1, 2, 1, 2, 4, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 3, 5, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 3, 1, 3, 2, 2, 1, 4, 6, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 2, 1, 3, 1, 1, 2, 1, 3, 1, 4, 2, 3, 1, 5, 7, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 3, 1, 1, 2, 2, 2, 1, 1, 2
Offset: 1

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Author

Keywords

Comments

The signature of a multiset is a partition consisting of the repetition factors of the original partition. Regarding a partition as a multiset, the signature of a partition is defined. E.g., [1,1,3,4,4] = [1^2,3^1,4^2], so the repetition factors are 2,1,2, making the signature [1,2,2] = [1,2^2]. Partitions are written here in increasing part size, so [1,2^2] is 1,2,2, not 2,2,1. - Edited by Franklin T. Adams-Watters, Jul 09 2012
The sum (or order) of the signature is the number of parts of the original partition and the number of parts of the signature is the number of distinct parts of the original partition.

Examples

			[1];
[1], [2];
[1], [1,1], [3];
[1], [1,1], [2], [1,2], [4];
...
From _Hartmut F. W. Hoft_, Apr 25 2015: (Start)
Extending the triangle to rows 5 and 6 where row headings indicate the number of elements in the underlying partitions. Brackets group the multiplicities of a single partition.
    row 5         row 6
1:  [1]           [1]
2:  [1,1] [1,1]   [1,1] [1,1] [2]
3:  [1,2] [1,2]   [1,2] [1,1,1] [3]
4:  [1,3]         [1,3] [2,2]
5:  [5]           [1,4]
6:                [6]
(End)
		

Crossrefs

Cf. A036036, A113787, A115622, A103921 (part counts), A000070 (row counts).

Programs

  • Mathematica
    (* row[] and triangle[] compute structured rows of the triangle as laid out above *)
    mL[pL_] := Map[Last[Transpose[Tally[#]]]&, pL]
    row[n_] := Map[Map[Sort, mL[#]]&, GatherBy[Map[Sort, IntegerPartitions[n]], Length]]
    triangle[n_] := Map[row, Range[n]]
    a115621[n_]:= Flatten[triangle[n]]
    Take[a115621[8],105] (* data *)  (* Hartmut F. W. Hoft, Apr 25 2015 *)
    Map[Sort[#, Less] &, Table[Last /@ Transpose /@ Tally /@ Sort[Reverse /@ IntegerPartitions[n]], {n, 8}], 2]
  • SageMath
    from collections import Counter
    def A115621_row(n):
        h = lambda p: sorted(Counter(p).values())
        return flatten([h(p) for k in (0..n) for p in Partitions(n, length=k)])
    for n in (1..10): print(A115621_row(n)) # Peter Luschny, Nov 02 2019

A334440 Irregular triangle T(n,k) read by rows: row n lists numbers of distinct parts of the n-th integer partition in Abramowitz-Stegun (sum/length/lex) order.

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 2, 1, 1, 1, 2, 2, 1, 3, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 2, 1, 3, 2, 3, 2, 2, 3, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 1, 3, 2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 2, 2, 3
Offset: 0

Views

Author

Gus Wiseman, May 05 2020

Keywords

Comments

The total number of parts, counting duplicates, is A036043. The version for reversed partitions is A103921.

Examples

			Triangle begins:
  0
  1
  1 1
  1 2 1
  1 1 2 2 1
  1 2 2 2 2 2 1
  1 1 2 2 1 3 2 2 2 2 1
  1 2 2 2 2 2 3 2 2 3 2 2 2 2 1
  1 1 2 2 2 2 2 3 3 2 1 3 2 3 2 2 3 2 2 2 2 1
		

Crossrefs

Row lengths are A000041.
The number of not necessarily distinct parts is A036043.
The version for reversed partitions is A103921.
Ignoring length (sum/lex) gives A103921 (also).
a(n) is the number of distinct elements in row n of A334301.
The maximum part of the same partition is A334441.
Lexicographically ordered reversed partitions are A026791.
Reversed partitions in Abramowitz-Stegun (sum/length/lex) order are A036036.
Partitions in increasing-length colex order (sum/length/colex) are A036037.
Graded reverse-lexicographically ordered partitions are A080577.
Partitions counted by sum and number of distinct parts are A116608.
Graded lexicographically ordered partitions are A193073.
Partitions in colexicographic order (sum/colex) are A211992.
Partitions in dual Abramowitz-Stegun (sum/length/revlex) order are A334439.

Programs

  • Mathematica
    Join@@Table[Length/@Union/@Sort[IntegerPartitions[n]],{n,0,10}]

Formula

a(n) = A001221(A334433(n)).

A221913 Array of coefficients of numerator polynomials (divided by x) of the n-th approximation of the continued fraction x/(1+x/(2+x/(3+...

Original entry on oeis.org

1, 2, 6, 1, 24, 6, 120, 36, 1, 720, 240, 12, 5040, 1800, 120, 1, 40320, 15120, 1200, 20, 362880, 141120, 12600, 300, 1, 3628800, 1451520, 141120, 4200, 30, 39916800, 16329600, 1693440, 58800, 630, 1, 479001600, 199584000, 21772800, 846720, 11760, 42
Offset: 1

Views

Author

Wolfdieter Lang, Feb 23 2013

Keywords

Comments

The row length sequence of this array is 1 + floor((n-1)/2) = A008619(n-1), n >= 1.
The array of denominators is found under A084950.
The continued fraction 0 + K_{k=1..infinity}(x/k) = x/(1+x/(2+x/(3+... has n-th approximation P(n,x)/Q(n,x). These polynomials satisfy the recurrence q(n,x) = n*q(n-1,x) + x*q(n-2,x), for q replaced by P or Q with inputs P(-1,x) = 1, P(0,x) = 0 and Q(-1,x) = 0 and Q(0,1) = 1. The present array provides the coefficients for Phat(n,x) := P(n,x)/x = sum(a(n,m)*x^m,m=0..floor((n-1)/2)), n >= 1. The recurrence is that of q(n,x) and the inputs are Phat(-1,x) = 1/x and Phat(0,x) =0. For the Q(n,x) coefficients see the companion array A084950. The solution with input q(-1,x) = a and q(0,x) = b is then, due to linearity, q(a,b;n,x) = a*x*Phat(n,x) + b*Q(n,x). The motivation to consider the q(n,x) recurrence stems from e-mails from Gary Detlefs, who considered integer x and various inputs and gave explicit formulas.
This array coincides with the SW-NE diagonals of the coefficient array |A066667| or A105278 (taken with offset [0,0]) of the generalized Laguerre polynomials n!*L(1,n,x) (parameter alpha = 1).
The entries a(n,m) have a combinatorial interpretation in terms of certain so-called labeled Morse code polynomials using dots (length 1) and dashes (of length 2). a(n,m) is the number of possibilities to decorate the n-1 positions 2,...,n with m dashes, m from {0,1,...,floor((n-1)/2)}, and n-1-2*m dots. A dot at position k has a label k and each dash between two neighboring positions has a label x. a(n,m) is the sum of these labeled Morse codes with m dashes after the label x^m has been divided out. E.g., a(6,2) = 6 + 4 + 2 = 12 from the 3 codes: dash dash dot, dash dot dash,and dot dash dash, or (23)(45)6, (23)4(56) and 2(34)(56), and labels (which are in general multiplicative) 6*x^2, 4*x^2 and 2*x^2, respectively.
For general Morse code polynomials (Euler's continuants) see the Graham et al. reference given in A221915, p. 302. - Wolfdieter Lang, Feb 28 2013
Row sums Phat(n,1) = A001053(n+1), n >= 1. Alternating row sums Phat(n,-1) = A058798(n), n >= 1.
From Wolfdieter Lang, Mar 06 2013 (Start)
The recurrence for q(n,x) given above, can be transformed to the one of Bessel functions given in Abramowitz-Stegun (see A103921 for the reference) in the first line of eq. 9.1.27 on p. 361 via i^n*q(n,x)/sqrt(x)^n = C(n+1,-i*2*sqrt(x)) with the imaginary unit i, where C can stand for BesselJ or BesselY. In order to fix the two inputs for the Q or Phat polynomials (given above) one uses a linear combination of these two independent solutions. The Wronskian eq. 9.1.16, p. 360, is used to simplify the coefficients. One can also use an alternative version based on eqs. 9.6.3 and 9.6.5, p. 375, to trade the J and Y polynomials for I and K.
This produces the two explicit formulas given below, and also the two versions given for Q in A084950.
(End)
For large order n the behavior of the row polynomials Phat(n,x) (see above) is known from the one of Bessel functions. See a comment on asymptotics under A084950. This leads then to the limit for Phat(n,x)/n! given in the formula section. The limit for the continued fraction mentioned in the name and above is also found in this comment on A084950. - Wolfdieter Lang, Mar 08 2013
This is the unsigned Lah triangle read by ascending antidiagonals. Conversely, reading the given triangle beginning at the left in descending steps yields a row of the unsigned Lah triangle. This can be verified immediately by means of the explicit formulas. For example, [T(5,0), T(6,1), T(7,2), T(8,3), T(9,4)] is row 5 of A105278. - Peter Luschny, Dec 07 2019

Examples

			The irregular triangle a(n,m)  begins:
n\m          0          1         2        3      4    5  6
1:           1
2:           2
3:           6          1
4:          24          6
5:         120         36         1
6:         720        240        12
7:        5040       1800       120        1
8:       40320      15120      1200       20
9:      362880     141120     12600      300     1
10:    3628800    1451520    141120     4200    30
11:   39916800   16329600   1693440    58800    63     1
12:  479001600   19958400  21772800   846720  11760   42
13: 6227020800 2634508800 299376000 12700800 211680 1176  1
...
Recurrence (short version): a(6,1) = 6*36 + 24 = 240.
Recurrence (long version): a(6,1) = 2*4*36 + 24 - 4*3*6 = 240.
a(6,1) = binomial(4,1)*5!/2! = 4*3*4*5 = 240.
		

Crossrefs

Programs

  • Mathematica
    row[n_] := x/ContinuedFractionK[x, i, {i, 0, n}] // Simplify // Together // Numerator // CoefficientList[#, x]& // Rest;
    row /@ Range[12] // Flatten (* Jean-François Alcover, Oct 28 2019 *)

Formula

Recurrence (short version): a(n,m) = n*a(n-1,m) + a(n-2,m-1), n>=2, a(1,1) =1, a(n,-1) = 0, a(n,m) = 0 if n < 2*m+1. From the recurrence for the Phat(n,x) polynomials given in a comment above.
Recurrence (long version): a(n,m) = 2*(n-1-m)*a(n-1,m) + a(n-2,m-1) - (n-1-m)*(n-2-m)*a(n-2,m), n >= 1, a(1,0) = 1, a(n,-1) = 0, a(n,m) = 0 if n < 2*m + 1. From the recurrence for the unsigned generalized Laguerre polynomial with parameter alpha = 1. This recurrence can be simplified to the preceding short version, because the following explicit form follows from the one for the generalized Laguerre coefficients (which, in turn, derives from the Rodrigues formula and the Leibniz rule). This proves the relation a(n,m) = |Lhat(1,n-1-m,m)|, with the coefficients |Lhat(1,n,m)| = |A066667(n,m)| of the unsigned n!*L(1,n,x) Laguerre polynomials (parameter alpha = 1).
a(n,m) = binomial(n-1-m,m)*(n-m)!/(m+1)!, n >= 1, 0 <= m <= floor((n-1)/2).
For the e.g.f.s of the column sequences see A105278 (here with different offset, which could be obtained by integration).
E.g.f. for row polynomials gPhat(z,x) := Sum_{z>=0} Phat(n,x)*z^n = Pi*(BesselJ(1, 2*i*sqrt(x)*sqrt(1-z))*BesselY(1, 2*i*sqrt(x)) - BesselY(1, (2*i)*sqrt(x)*sqrt(1-z))*BesselJ(1, 2*i*sqrt(x)))/sqrt(1-z) with Bessel functions and the imaginary unit i = sqrt(-1). Phat(0,x) = 0.
From Wolfdieter Lang, Mar 06 2013 (Start)
For the row polynomials one finds Phat(n,x) = Pi*(z/2)^n*(BesselY(1,z)* BesselJ(n+1,z) - BesselJ(1,z)*BesselY(n+1,z)) where z := -i*2*sqrt(x) and the i is the imaginary unit. An alternative form is Phat(n,x) = 2*(w/2)^n*(BesselI(1,w)*BesselK(n+1,w) + BesselK(1,w)*BesselI(n+1,w)*(-1)^(n+1)), n >= 1, where w := -2*sqrt(x). See a comment above for the derivation. (End)
Limit_{n -> oo} Phat(n,x)/n! = BesselI(1,2*sqrt(x))/sqrt(x). See a comment above. - Wolfdieter Lang, Mar 08 2013

A238966 The number of distinct primes in divisor lattice in canonical order.

Original entry on oeis.org

0, 1, 1, 2, 1, 2, 3, 1, 2, 2, 3, 4, 1, 2, 2, 3, 3, 4, 5, 1, 2, 2, 3, 2, 3, 4, 3, 4, 5, 6, 1, 2, 2, 3, 2, 3, 4, 3, 3, 4, 5, 4, 5, 6, 7, 1, 2, 2, 3, 2, 3, 4, 2, 3, 3, 4, 5, 3, 4, 4, 5, 6, 4, 5, 6, 7, 8, 1, 2, 2, 3, 2, 3, 4, 2, 3, 3, 4, 5, 3, 3, 4, 4, 5, 6, 3, 4, 5, 4, 5, 6, 7, 5, 6, 7, 8, 9
Offset: 0

Views

Author

Sung-Hyuk Cha, Mar 07 2014

Keywords

Comments

After a(0) = 0, this appears to be the same as A128628. - Gus Wiseman, May 24 2020
Also the number of parts in the n-th integer partition in graded reverse-lexicographic order (A080577). - Gus Wiseman, May 24 2020

Examples

			Triangle T(n,k) begins:
  0;
  1;
  1, 2;
  1, 2, 3;
  1, 2, 2, 3, 4;
  1, 2, 2, 3, 3, 4, 5;
  1, 2, 2, 3, 2, 3, 4, 3, 4, 5, 6;
  ...
		

Crossrefs

Row sums are A006128.
Cf. A036043 in canonical order.
Row lengths are A000041.
The generalization to compositions is A000120.
The sum of the partition is A036042.
The lexicographic version (sum/lex) is A049085.
Partition lengths of A080577.
The partition has A115623 distinct elements.
The Heinz number of the partition is A129129.
The colexicographic version (sum/colex) is A193173.
The maximum of the partition is A331581.
Partitions in lexicographic order (sum/lex) are A193073.
Partitions in colexicographic order (sum/colex) are A211992.

Programs

  • Maple
    o:= proc(n) option remember; nops(ifactors(n)[2]) end:
    b:= (n, i)-> `if`(n=0 or i=1, [[1$n]], [map(x->
        [i, x[]], b(n-i, min(n-i, i)))[], b(n, i-1)[]]):
    T:= n-> map(x-> o(mul(ithprime(i)^x[i], i=1..nops(x))), b(n$2))[]:
    seq(T(n), n=0..9);  # Alois P. Heinz, Mar 26 2020
  • Mathematica
    revlexsort[f_,c_]:=OrderedQ[PadRight[{c,f}]];
    Table[Length/@Sort[IntegerPartitions[n],revlexsort],{n,0,8}] (* Gus Wiseman, May 24 2020 *)
    b[n_, i_] := b[n, i] = If[n == 0 || i == 1, {Table[1, {n}]}, Join[ Prepend[#, i]& /@ b[n - i, Min[n - i, i]], b[n, i - 1]]];
    P[n_] := P[n] = Product[Prime[i]^#[[i]], {i, 1, Length[#]}]& /@ b[n, n];
    T[n_, k_] := PrimeNu[P[n][[k + 1]]];
    Table[T[n, k], {n, 0, 9}, {k, 0, Length[P[n]] - 1}] // Flatten (* Jean-François Alcover, Jan 03 2022, after Alois P. Heinz in A063008 *)
  • PARI
    Row(n)={apply(s->#s, vecsort([Vecrev(p) | p<-partitions(n)], , 4))}
    { for(n=0, 8, print(Row(n))) } \\ Andrew Howroyd, Mar 25 2020

Formula

T(n,k) = A001221(A063008(n,k)). - Andrew Howroyd, Mar 25 2020
a(n) = A001222(A129129(n)). - Gus Wiseman, May 24 2020

Extensions

Offset changed and terms a(50) and beyond from Andrew Howroyd, Mar 25 2020

A333486 Length of the n-th reversed integer partition in graded reverse-lexicographic order. Partition lengths of A228531.

Original entry on oeis.org

0, 1, 1, 2, 1, 2, 3, 1, 2, 2, 3, 4, 1, 2, 2, 3, 3, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4, 4, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 3, 4, 4, 5, 5, 6, 7, 1, 2, 2, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 4, 5, 5, 6, 6, 7, 8, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 5, 6, 6, 7, 7, 8, 9
Offset: 0

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Author

Gus Wiseman, May 23 2020

Keywords

Examples

			Triangle begins:
  0
  1
  1 2
  1 2 3
  1 2 2 3 4
  1 2 2 3 3 4 5
  1 2 2 3 2 3 3 4 4 5 6
  1 2 2 3 2 3 3 4 3 4 4 5 5 6 7
  1 2 2 2 3 3 4 2 3 3 4 3 4 4 5 4 5 5 6 6 7 8
		

Crossrefs

Row lengths are A000041.
The generalization to compositions is A000120.
Row sums are A006128.
The same partition has sum A036042.
The length-sensitive version (sum/length/revlex) is A036043.
The colexicographic version (sum/colex) is A049085.
The same partition has minimum A182715.
The lexicographic version (sum/lex) is A193173.
The tetrangle of these partitions is A228531.
The version for non-reversed partitions is A238966.
The same partition has Heinz number A334436.
Reversed partitions in Abramowitz-Stegun order (sum/length/lex) are A036036.
Partitions in lexicographic order (sum/lex) are A193073.
Partitions in colexicographic order (sum/colex) are A211992.
Partitions in opposite Abramowitz-Stegun order (sum/length/revlex) are A334439.

Programs

  • Mathematica
    revlexsort[f_,c_]:=OrderedQ[PadRight[{c,f}]];
    Table[Length/@Sort[Reverse/@IntegerPartitions[n],revlexsort],{n,0,8}]

A092905 Triangle, read by rows, such that the partial sums of the n-th row form the n-th diagonal, for n>=0, where each row begins with 1.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 2, 1, 1, 4, 4, 2, 1, 1, 5, 6, 4, 2, 1, 1, 6, 9, 7, 4, 2, 1, 1, 7, 12, 11, 7, 4, 2, 1, 1, 8, 16, 16, 12, 7, 4, 2, 1, 1, 9, 20, 23, 18, 12, 7, 4, 2, 1, 1, 10, 25, 31, 27, 19, 12, 7, 4, 2, 1, 1, 11, 30, 41, 38, 29, 19, 12, 7, 4, 2, 1, 1, 12, 36, 53, 53, 42, 30, 19, 12, 7, 4, 2, 1
Offset: 0

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Author

Paul D. Hanna, Mar 12 2004

Keywords

Comments

Row sums form A000070, which is the partial sums of the partition numbers (A000041). Rows read backwards converge to the row sums (A000070).
From Alford Arnold, Feb 07 2010: (Start)
The table can also be generated by summing sequences embedded within Table A008284
For example,
1 1 1 1 ... yields 1 2 3 4 ...
1 1 2 2 3 3 ... yields 1 2 4 6 9 12 ...
1 1 2 3 4 5 7 ... yields 1 2 4 7 11 16 ...
(End)
T(n,k) is also count of all 'replacable' cells in the (Ferrers plots of) the partitions on n in exactly k parts. [Wouter Meeussen, Sep 16 2010]
From Wolfdieter Lang, Dec 03 2012: (Start)
The triangle entry T(n,k) is obtained from triangle A072233 by summing the entries of column k up to n (see the partial sum type o.g.f. given by Vladeta Jovovic in the formula section).
Therefore, the o.g.f. for the sequence in column k is x^k/((1-x)* product(1-x^j,j=1..k)).
The triangle with entry a(n,m) = T(n-1,m-1), n >= 1, m = 1, ..., n, is obtained from the partition array A103921 when in row n all entries belonging to part number m are summed (a conjecture). (End)

Examples

			The fourth row (n=3) is {1,3,2,1} and the fourth diagonal is the partial sums of the fourth row: {1,4,6,7,7,7,7,7,...}.
The triangle T(n,k) begins:
n\k 0  1  2  3  4  5  6  7  8  9 10 11 12  ...
0   1
1   1  1
2   1  2  1
3   1  3  2  1
4   1  4  4  2  1
5   1  5  6  4  2  1
6   1  6  9  7  4  2  1
7   1  7 12 11  7  4  2  1
8   1  8 16 16 12  7  4  2  1
9   1  9 20 23 18 12  7  4  2  1
10  1 10 25 31 27 19 12  7  4  2  1
11  1 11 30 41 38 29 19 12  7  4  2  1
12  1 12 36 53 53 42 30 19 12  7  4  2  1
... Reformatted by _Wolfdieter Lang_, Dec 03 2012
T(5,3)=4 because the partitions of 5 in exactly 3 parts are 221 and 311, and they give rise to partitions of 4 in four ways: 221->22 and 211, 311->211 and 31, since both their Ferrers plots have 2 'mobile cells' each. [_Wouter Meeussen_, Sep 16 2010]
T(5,3) = a(6,4) = 4 because the partitions of 6 with 4 parts are 1113 and 1122, with the number of distinct parts 2 and 2, respectively, summing to 4 (see the array A103921). An example for the conjecture given as comment above. - _Wolfdieter Lang_, Dec 03 2012
		

Crossrefs

Antidiagonal sums form the partition numbers (A000041).
Cf. A000070.
Cf. A008284. [Alford Arnold, Feb 07 2010]

Programs

Formula

T(n, k) = sum_{j=0..k} T(n-k, j), with T(n, 0) = 1 for all n>=0. A000070(n) = sum_{k=0..n} T(n, k).
O.g.f.: (1/(1-y))*(1/Product(1-x*y^k, k=1..infinity)). - Vladeta Jovovic, Jan 29 2005

Extensions

Several corrections by Wolfdieter Lang, Dec 03 2012

A111786 Array used to obtain the complete symmetric function in n variables in terms of the elementary symmetric functions; irregular triangle T(n,k), read by rows, with n >= 1 and 1 <= k <= A000041(n).

Original entry on oeis.org

1, -1, 1, 1, -2, 1, -1, 2, 1, -3, 1, 1, -2, -2, 3, 3, -4, 1, -1, 2, 2, 1, -3, -6, -1, 4, 6, -5, 1, 1, -2, -2, -2, 3, 6, 3, 3, -4, -12, -4, 5, 10, -6, 1, -1, 2, 2, 2, 1, -3, -6, -6, -3, -3, 4, 12, 6, 12, 1, -5, -20, -10, 6, 15, -7, 1, 1, -2, -2, -2, -2, 3, 6, 6, 3, 3, 6, 1, -4, -12, -12, -12, -12, -4, 5, 20, 10, 30, 5, -6, -30, -20, 7, 21, -8, 1, -1
Offset: 1

Views

Author

Wolfdieter Lang, Aug 23 2005

Keywords

Comments

The unsigned numbers give A048996. They are not listed on pp. 831-832 of Abramowitz and Stegun (reference given in A103921). One could call these numbers M_0 (like M_1, M_2, M_3 given in A036038, A036039, A036040, resp.).
The sequence of row lengths is A000041(n) (partition numbers).
The sign is (-1)^(n + m(n,k)) with m(n,k) the number of parts of the k-th partition of n taken in the mentioned order. For m(n,k), see A036043.
The row sum is 1 for n = 1, and 0 otherwise. The unsigned row sum is 2^(n-1) = A000079(n-1) for n >= 1.
The complete symmetric polynomial is also h(n; a[1],...,a[n]) = Det(A_n) with the matrix elements of the n X n matrix A_n given by A_n(k, k+1) = 1 for 1 <= k < n, A(k, m) = a[k-m+1] for n >= k >= m >= 1, and 0 otherwise. [For an explanation of this statement, see the example for n = 4 below. See also p. 3 in MacMahon (1960).]

Examples

			Triangle T(n,k) (with rows n >= 1 and columns k >= 1) begins as follows:
   1;
  -1,  1;
   1, -2,  1;
  -1,  2,  1, -3,  1;
   1, -2, -2,  3,  3, -4,  1;
  -1,  2,  2,  1, -3, -6, -1, 4, 6, -5, 1,
   ...
h(4; a[1],...,a[4])= -1*a[4] + 2*a[1]*a[3] + 1*a[2]^2 - 3*a[1]^2*a[2] + a[1]^4.
Consider variables x_1, x_2, x_3, x_4, and let a[1] = Sum_i x_i, a[2] = Sum_{i,j} x_i*x_j, a[3] = Sum_{i,j,k} x_i*x_j*x_k, and a[4] = x1*x2*x3*x4, where in all the sums no term is repeated twice.
Then h(4; a[1],...,a[4]) = Sum_i x_i^4 + Sum_{i,j} x_i^3*x_j + Sum_{i,j} x_i^2*x_j^2 + Sum_{i,j,k} x_i^2*x_j*x_k + Sum_{i,j,k,m} x_i*x_j*x_k*x_m, where again in all the sums no term is repeated twice. Thus, indeed, h is the complete symmetric polynomial in four variables x_1, x_2, x_3, x_4.
		

References

  • V. Krishnamurthy, Combinatorics, Ellis Horwood, Chichester, 1986, p. 55, eqs. (48) and (50).

Crossrefs

Formula

The complete symmetric row polynomials h(n; a[1], ..., a[n]):= sum k over partitions of n of T(n, k)* A[k], with A[k] := a[1]^e(k, 1) * a[2]^e(k, 2) * ... * a[n]^e(k, n) is the k-th partition of n, in Abramowitz-Stegun order (see A105805 for this reference), is [1^e(k, 1), 2^e(k, 2), ..., n^e(k, n)], for k = 1..p(n), where p(n) = A000041(n) (partition numbers).
G.f.: A(x) = 1/(1 + Sum_{j = 1..infinity} (-1)^j * a[j]).
T(n, k) is the coefficient of x^n and a[1]^e(k, 1) * a[2]^e(k, 2) * ... * a[n]^e(k, n) in A(x) if the k-th partition of n, counted using the Abramowitz-Stegun order, is [1^e(k, 1), 2^e(k, 2), ..., n^e(k, n)] with e(k, j) >= 0 (and if e(k, j) = 0 then j^0 is not recorded).
T(n, k) = (-1)^(n + m(n, k)) * m(n, k)!/(Product_{j = 1..n} e(k, j)!), where m(n, k) := Sum_{j = 1..n} e(k, j), with [1^e(k, 1), 2^e(k, 2), ..., n^e(k, n)] being the k-th partition of n in the mentioned order. Here m(n, k) is the number of parts of the k-th partition of n. For m(n,k), see A036043.

Extensions

Various sections edited by Petros Hadjicostas, Dec 15 2019
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