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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A209936 Triangle of multiplicities of k-th partition of n corresponding to sequence A080577. Multiplicity of a given partition of n into k parts is the number of ways parts can be selected from k distinguishable bins. See the example.

Original entry on oeis.org

1, 2, 1, 3, 6, 1, 4, 12, 6, 12, 1, 5, 20, 20, 30, 30, 20, 1, 6, 30, 30, 60, 15, 120, 60, 20, 90, 30, 1, 7, 42, 42, 105, 42, 210, 140, 105, 105, 420, 105, 140, 210, 42, 1, 8, 56, 56, 168, 56, 336, 280, 28, 336, 168, 840, 280, 168, 420, 840, 1120, 168, 70, 560, 420, 56, 1
Offset: 1

Views

Author

Sergei Viznyuk, Mar 15 2012

Keywords

Comments

Differs from A035206 after position 21.
Differs from A210238 after position 21.
The n-th row of the triangle, written as a column vector v(n), satisfies K . v(n) = #SSYT(lambda,n) where K is the Kostka matrix of order n, and #SSYT(lambda,n) is the count of semi-standard Young tableaux in n variables of the partitions of n. - Wouter Meeussen, Jan 27 2025

Examples

			Triangle begins:
  1
  2, 1
  3, 6, 1
  4, 12, 6, 12, 1
  5, 20, 20, 30, 30, 20, 1
  6, 30, 30, 60, 15, 120, 60, 20, 90, 30, 1
  7, 42, 42, 105, 42, 210, 140, 105, 105, 420, 105, 140, 210, 42, 1
  ...
Thus for n=3 (third row) the partitions of n=3 are:
  3+0+0  0+3+0  0+0+3   (multiplicity=3),
  2+1+0  2+0+1  1+2+0  1+0+2  0+2+1  0+1+2  (multiplicity=6),
  1+1+1  (multiplicity=1).
		

Crossrefs

Row lengths give A000041.
Row sums give A088218.

Programs

  • Mathematica
    Apply[Multinomial,Last/@Tally[#]&/@PadRight[IntegerPartitions[n]],1] (* Wouter Meeussen, Jan 26 2025 *)

A322762 Irregular triangle read by rows: to get row n, take partitions of n ordered as in A080577, and in each partition, change each j-th occurrence of k to j; use compressed notation as in A322761.

Original entry on oeis.org

1, 1, 12, 1, 11, 123, 1, 11, 12, 112, 1234, 1, 11, 11, 112, 121, 1123, 12345, 1, 11, 11, 112, 12, 111, 1123, 123, 1212, 11234, 123456, 1, 11, 11, 112, 11, 111, 1123, 121, 112, 1112, 11234, 1231, 12123, 112345, 1234567, 1, 11, 11, 112, 11, 111, 1123, 12, 111
Offset: 1

Views

Author

N. J. A. Sloane, Dec 30 2018

Keywords

Examples

			Triangle begins:
  1,
  1, 12,
  1, 11, 123,
  1, 11, 12, 112, 1234,
  1, 11, 11, 112, 121, 1123, 12345,
  1, 11, 11, 112, 12, 111, 1123, 123, 1212, 11234, 123456,
  ...
For example, the 11 partitions of 6 are:
6, 51, 42, 411, 33, 321, 3111, 222, 2211, 21111, 111111,
and applying the transformation we get:
1, 11, 11, 112, 12, 111, 1123, 123, 1212, 11234, 123456.
		

References

  • D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.2.1.5, Problem 73, pp. 415, 761.

Crossrefs

Programs

  • Maple
    b:= (n, i)-> `if`(n=0 or i=1, [cat($1..n)], [(t->
        seq(map(x-> cat($1..(t+1-j), x), b(n-i*(t+1-j)
        , i-1))[], j=1..t))(iquo(n, i)), b(n, i-1)[]]):
    T:= n-> map(parse, b(n$2))[]:
    seq(T(n), n=1..10);  # Alois P. Heinz, Dec 30 2018

Extensions

More terms from Alois P. Heinz, Dec 30 2018

A322763 Irregular triangle read by rows: to get row n, take partitions of n ordered as in A080577, and in each partition, change each j-th occurrence of k to j; use uncompressed notation as in A080577.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Dec 30 2018

Keywords

Comments

The compressed form seems easier to understand. This is A322762 but with each partition, after it has been transformed, written as the string of its parts.

Examples

			In compressed form (see A322762) triangle begins:
  1,
  1, 12,
  1, 11, 123,
  1, 11, 12, 112, 1234,
  1, 11, 11, 112, 121, 1123, 12345,
  1, 11, 11, 112, 12, 111, 1123, 123, 1212, 11234, 123456,
  ...
For example, the 11 partitions of 6 are:
6, 51, 42, 411, 33, 321, 3111, 222, 2211, 21111, 111111,
and applying the transformation we get:
1, 11, 11, 112, 12, 111, 1123, 123, 1212, 11234, 123456.
In the uncompressed notation the triangle begins:
  {1},
  {1}, {1,2},
  {1}, {1,1}, {1,2,3},
  {1}, {1,1}, {1,2}, {1,1,2}, {1,2,3,4},
  {1}, {1,1}, {1,1}, {1,1,2}, {1,2,1}, {1,1,2,3}, {1,2,3,4,5},
  ...
		

References

  • D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.2.1.5, Problem 73, pp. 415, 761.

Crossrefs

Programs

  • Maple
    b:= (n, i)-> `if`(n=0 or i=1, [[$1..n]], [(t->
        seq(map(x-> [$1..(t+1-j), x[]], b(n-i*(t+1-j)
        , i-1))[], j=1..t))(iquo(n, i)), b(n, i-1)[]]):
    T:= n-> map(x-> x[], b(n$2))[]:
    seq(T(n), n=1..10);  # Alois P. Heinz, Dec 30 2018

Extensions

More terms from Alois P. Heinz, Dec 30 2018

A261209 First differences of partitions of n in the ordering A080577.

Original entry on oeis.org

1, 2, 0, 1, 3, 1, 1, 0, 0, 1, 4, 2, 1, 0, 2, 1, 0, 1, 0, 0, 0, 1, 5, 3, 1, 1, 2, 2, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 6, 4, 1, 2, 2, 3, 0, 1, 0, 3, 1, 1, 1, 2, 0, 0, 1, 0, 0, 2, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1
Offset: 1

Views

Author

Peter Luschny, Aug 12 2015

Keywords

Examples

			For n=6:
[6]
[4, 1]
[2, 2]
[3, 0, 1]
[0, 3]
[1, 1, 1]
[2, 0, 0, 1]
[0, 0, 2]
[0, 1, 0, 1]
[1, 0, 0, 0, 1]
[0, 0, 0, 0, 0, 1]
		

Crossrefs

Cf. A080577.

Programs

  • Sage
    def A261209(n):
        delta = lambda p: [p[i]-p[i+1] for i in (0..len(p)-2)]+[p[-1]] if p else []
        return [delta(p) for p in Partitions(n)]
    [A261209(n) for n in (1..6)]

A332567 T(n,k) is the k-th partition of n in graded reverse lexicographic ordering (A080577) encoded as concatenation of parts which are represented in (zeroless) bijective base-9 numeration (A052382) and separated by zeros; triangle T(n,k), n >= 0, 1 <= k <= A000041(n), read by rows.

Original entry on oeis.org

0, 1, 2, 101, 3, 201, 10101, 4, 301, 202, 20101, 1010101, 5, 401, 302, 30101, 20201, 2010101, 101010101, 6, 501, 402, 40101, 303, 30201, 3010101, 20202, 2020101, 201010101, 10101010101, 7, 601, 502, 50101, 403, 40201, 4010101, 30301, 30202, 3020101, 301010101
Offset: 0

Views

Author

Alois P. Heinz, Feb 16 2020

Keywords

Comments

The encoding used here allows a lossless and human-readable compression of all partitions. To decode a term replace the zeros with commas and read the parts in bijective base 9.
The empty partition is encoded as 0.

Examples

			T(6,6) = 30201 encodes the 6th partition of 6: [3,2,1].
T(10,1) = 11 encodes the 1st partition of 10: [10].
T(23,23) = 18040101 encodes the 23rd partition of 23: [17,4,1,1].
Triangle T(n,k) begins:
   0;
   1;
   2, 101;
   3, 201, 10101;
   4, 301, 202, 20101, 1010101;
   5, 401, 302, 30101, 20201, 2010101, 101010101;
   6, 501, 402, 40101, 303, 30201, 3010101, 20202, 2020101, ...
   7, 601, 502, 50101, 403, 40201, 4010101, 30301, 30202, ...
   8, 701, 602, 60101, 503, 50201, 5010101, 404, 40301, 40202, ...
   9, 801, 702, 70101, 603, 60201, 6010101, 504, 50301, 50202, ...
  11, 901, 802, 80101, 703, 70201, 7010101, 604, 60301, 60202, ...
  ...
		

Crossrefs

Column k=1 gives A052382 (for n>0).
Last row elements give A094028(n-1) (for n>0).

Programs

  • Maple
    g:= proc(n) option remember; local d, m, l; m, l:= n, "";
          while m>0 do d:= irem(m, 9, 'm');
            if d=0 then d:=9; m:= m-1 fi; l:= d, l
          od; parse(cat(l))
        end:
    b:= (n, i)-> `if`(n=0, [""], `if`(i<1, [], [map(x-> cat(
         0, g(i), x), b(n-i, min(n-i, i)))[], b(n, i-1)[]])):
    T:= n-> map(x-> parse(cat(0, x)), b(n$2))[]:
    seq(T(n), n=0..10);

A260533 Table of partition coefficients read by rows. The coefficient of a partition p is Product_{j=1..length(p)-1} C(p[j], p[j+1]). Row n lists the coefficients of the partitions of n in the ordering A080577, for n>=1.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 1, 2, 1, 1, 4, 3, 3, 2, 2, 1, 1, 5, 6, 4, 1, 6, 3, 1, 2, 2, 1, 1, 6, 10, 5, 4, 12, 4, 3, 3, 6, 3, 2, 2, 2, 1, 1, 7, 15, 6, 10, 20, 5, 1, 12, 6, 12, 4, 3, 3, 6, 6, 3, 1, 2, 2, 2, 1
Offset: 1

Views

Author

Peter Luschny, Jul 28 2015

Keywords

Comments

The triangle is a refinement of Pascal's triangle A007318.

Examples

			The signed version of the triangle starts:
[1]
[-1, 1]
[1, -2, 1]
[-1, 3, -1, -2, 1]
[1, -4, 3, 3, -2, -2, 1]
[-1, 5, -6, -4, 1, 6, 3, -1, -2, -2, 1]
Adding adjacent coefficients with equal sign reduces the triangle to the matrix inverse of Pascal's triangle (A130595).
.
The q-polynomials defined by Cigler start:
[0]  1;
[1]  1, q;
[2]  1, 2*q, q^3;
[3]  1, 3*q, q^2+2*q^3,   q^6;
[4]  1, 4*q, 3*q^2+3*q^3, 2*q^4+2*q^6,     q^10;
[5]  1, 5*q, 6*q^2+4*q^3, q^3+6*q^4+3*q^6, q^6+2*q^7+2*q^10, q^15;
		

Crossrefs

Cf. A007318, A080577, A130595, A269941 (expanded form).

Programs

  • Maple
    with(combstruct): with(ListTools):
    PartitionCoefficients := proc(n) local L, iter, p;
    iter := iterstructs(Partition(n)): L := []:
    while not finished(iter) do
       p := Reverse(nextstruct(iter)):
       L := [mul(binomial(p[j], p[j+1]), j=1..nops(p)-1), op(L)]
    od end:
    for n from 1 to 6 do PartitionCoefficients(n) od;
    # Alternative, using Cigler's recurrence for the q-polynomials:
    C := proc(n, k, q) local j;
    if k = 0 then q^binomial(n + 1, 2) elif n = 0 then n^k else
    add(q^binomial(j + 1, 2)*C(n - j - 1, k - 1, q), j = 0..n - k) fi end:
    p := n -> local k; add(C(n, n - k, q)*x^k, k = 0..n):
    row := n -> local k; seq(sort(coeff(expand(p(n)), x, k), [q], ascending), k=0..n):
    for n from 0 to 5 do row(n) od;  # Peter Luschny, Aug 24 2024
  • Sage
    PartitionCoeff = lambda p: mul(binomial(p[j], p[j+1]) for j in range(len(p)-1))
    PartitionCoefficients = lambda n: [PartitionCoeff(p) for p in Partitions(n)]
    for n in (1..7): print(PartitionCoefficients(n))

Formula

Let P = Partitions(n, k) denote the set of partitions p of n with largest part k. Then Sum_{p in P} PartitionCoefficient(p) = binomial(n-1,k-1) for n>=0 and k>=0 (assuming binomial(-1,-1) = 1).

A366105 a(n) is the number of parts in the n-th partition of n when the partitions are listed in graded reverse lexicographic order (cf. A080577, as in Mathematica).

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Oct 03 2023

Keywords

Comments

Conjecture 1. Every integer m > 1 occurs infinitely many times. (For example, 2 occurs for n = 2,8,13,20,31,46,68,....)
Conjecture 2. Let f(n) be the greatest (i.e., the first) part in the n-th partition of n. Then for every integer m, there exists an index i such that f(i+1), f(i+2), ..., f(i+m) are consecutive integers.

Examples

			The partitions of 5, listed in reverse-lexicographic order, are (5, 41, 32, 311, 221, 2111, 11111); the 5th in this list is 221, with length 3, so that a(5) = 3.
		

Crossrefs

Programs

  • Mathematica
    Table[Length[IntegerPartitions[n][[n]]], {n, 1, 40}]

A066099 Triangle read by rows, in which row n lists the compositions of n in reverse lexicographic order.

Original entry on oeis.org

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

Views

Author

Alford Arnold, Dec 30 2001

Keywords

Comments

The representation of the compositions (for fixed n) is as lists of parts, the order between individual compositions (for the same n) is (list-)reversed lexicographic; see the example by Omar E. Pol. - Joerg Arndt, Sep 03 2013
This is the standard ordering for compositions in this database; it is similar to the Mathematica ordering for partitions (A080577). Other composition orderings include A124734 (similar to the Abramowitz & Stegun ordering for partitions, A036036), A108244 (similar to the Maple partition ordering, A080576), etc (see crossrefs).
Factorize each term in A057335; sequence records the values of the resulting exponents. It also runs through all possible permutations of multiset digits.
This can be regarded as a table in two ways: with each composition as a row, or with the compositions of each integer as a row. The first way has A000120 as row lengths and A070939 as row sums; the second has A001792 as row lengths and A001788 as row sums. - Franklin T. Adams-Watters, Nov 06 2006
This sequence includes every finite sequence of positive integers. - Franklin T. Adams-Watters, Nov 06 2006
Compositions (or ordered partitions) are also generated in sequence A101211. - Alford Arnold, Dec 12 2006
The equivalent sequence for partitions is A228531. - Omar E. Pol, Sep 03 2013
The sole partition of zero has no components, not a single component of length one. Hence the first nonempty row is row 1. - Franklin T. Adams-Watters, Apr 02 2014 [Edited by Andrey Zabolotskiy, May 19 2018]
See sequence A261300 for another version where the terms of each composition are concatenated to form one single integer: (0, 1, 2, 11, 3, 21, 12, 111,...). This also shows how the terms can be obtained from the binary numbers A007088, cf. Arnold's first Example. - M. F. Hasler, Aug 29 2015
The k-th composition in the list is obtained by taking the set of positions of 1's in the reversed binary expansion of k, prepending 0, taking first differences, and reversing again. This is described as the standard ordering used in the OEIS, although the sister sequence A228351 is also sometimes considered to be canonical. Both sequences define a bijective correspondence between nonnegative integers and integer compositions. - Gus Wiseman, May 19 2020
First differences of A030303 = positions of bits 1 in the concatenation A030190 (= A030302) of numbers written in binary (A007088). - Indices of record values (= first occurrence of n) are given by A005183: a(A005183(n)) = n, cf. FORMULA for more. - M. F. Hasler, Oct 12 2020
The geometric mean approaches the Somos constant (A112302). - Jwalin Bhatt, Feb 10 2025

Examples

			A057335 begins 1 2 4 6 8 12 18 30 16 24 36 ... so we can write
  1 2 1 3 2 1 1 4 3 2 2 1 1 1 1 ...
  . . 1 . 1 2 1 . 1 2 1 3 2 1 1 ...
  . . . . . . 1 . . . 1 . 1 2 1 ...
  . . . . . . . . . . . . . . 1 ...
and the columns here gives the rows of the triangle, which begins
  1
  2; 1 1
  3; 2 1; 1 2; 1 1 1
  4; 3 1; 2 2; 2 1 1; 1 3; 1 2 1; 1 1 2; 1 1 1 1
  ...
From _Omar E. Pol_, Sep 03 2013: (Start)
Illustration of initial terms:
  -----------------------------------
  n  j       Diagram   Composition j
  -----------------------------------
  .               _
  1  1           |_|   1;
  .             _ _
  2  1         |  _|   2,
  2  2         |_|_|   1, 1;
  .           _ _ _
  3  1       |    _|   3,
  3  2       |  _|_|   2, 1,
  3  3       | |  _|   1, 2,
  3  4       |_|_|_|   1, 1, 1;
  .         _ _ _ _
  4  1     |      _|   4,
  4  2     |    _|_|   3, 1,
  4  3     |   |  _|   2, 2,
  4  4     |  _|_|_|   2, 1, 1,
  4  5     | |    _|   1, 3,
  4  6     | |  _|_|   1, 2, 1,
  4  7     | | |  _|   1, 1, 2,
  4  8     |_|_|_|_|   1, 1, 1, 1;
(End)
		

Crossrefs

Lists of compositions of integers: this sequence (reverse lexicographic order; minus one gives A108730), A228351 (reverse colexicographic order - every composition is reversed; minus one gives A163510), A228369 (lexicographic), A228525 (colexicographic), A124734 (length, then lexicographic; minus one gives A124735), A296774 (length, then reverse lexicographic), A337243 (length, then colexicographic), A337259 (length, then reverse colexicographic), A296773 (decreasing length, then lexicographic), A296772 (decreasing length, then reverse lexicographic), A337260 (decreasing length, then colexicographic), A108244 (decreasing length, then reverse colexicographic), also A101211 and A227736 (run lengths of bits).
Cf. row length and row sums for different splittings into rows: A000120, A070939, A001792, A001788.
Cf. lists of partitions of integers, or multisets of integers: A026791 and crosserfs therein, A112798 and crossrefs therein.
See link for additional crossrefs pertaining to standard compositions.
A related ranking of finite sets is A048793/A272020.

Programs

  • Haskell
    a066099 = (!!) a066099_list
    a066099_list = concat a066099_tabf
    a066099_tabf = map a066099_row [1..]
    a066099_row n = reverse $ a228351_row n
    -- (each composition as a row)
    -- Peter Kagey, Aug 25 2016
    
  • Mathematica
    Table[FactorInteger[Apply[Times, Map[Prime, Accumulate @ IntegerDigits[n, 2]]]][[All, -1]], {n, 41}] // Flatten (* Michael De Vlieger, Jul 11 2017 *)
    stc[n_] := Differences[Prepend[Join @@ Position[Reverse[IntegerDigits[n, 2]], 1], 0]] // Reverse;
    Table[stc[n], {n, 0, 20}] // Flatten (* Gus Wiseman, May 19 2020 *)
    Table[Reverse @ LexicographicSort @ Flatten[Permutations /@ Partitions[n], 1], {n, 10}] // Flatten (* Eric W. Weisstein, Jun 26 2023 *)
  • PARI
    arow(n) = {local(v=vector(n),j=0,k=0);
       while(n>0,k++; if(n%2==1,v[j++]=k;k=0);n\=2);
       vector(j,i,v[j-i+1])} \\ returns empty for n=0. - Franklin T. Adams-Watters, Apr 02 2014
    
  • Python
    from itertools import islice
    from itertools import accumulate, count, groupby, islice
    def A066099_gen():
        for i in count(1):
            yield [len(list(g)) for _,g in groupby(accumulate(int(b) for b in bin(i)[2:]))]
    A066099 = list(islice(A066099_gen(), 120))  # Jwalin Bhatt, Feb 28 2025
  • Sage
    def a_row(n): return list(reversed(Compositions(n)))
    flatten([a_row(n) for n in range(1,6)]) # Peter Luschny, May 19 2018
    

Formula

From M. F. Hasler, Oct 12 2020: (Start)
a(n) = A030303(n+1) - A030303(n).
a(A005183(n)) = n; a(A005183(n)+1) = n-1 (n>1); a(A005183(n)+2) = 1. (End)

Extensions

Edited with additional terms by Franklin T. Adams-Watters, Nov 06 2006
0th row removed by Andrey Zabolotskiy, May 19 2018

A215366 Triangle T(n,k) read by rows in which n-th row lists in increasing order all partitions lambda of n encoded as Product_{i in lambda} prime(i); n>=0, 1<=k<=A000041(n).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 7, 9, 10, 12, 16, 11, 14, 15, 18, 20, 24, 32, 13, 21, 22, 25, 27, 28, 30, 36, 40, 48, 64, 17, 26, 33, 35, 42, 44, 45, 50, 54, 56, 60, 72, 80, 96, 128, 19, 34, 39, 49, 52, 55, 63, 66, 70, 75, 81, 84, 88, 90, 100, 108, 112, 120, 144, 160, 192, 256
Offset: 0

Views

Author

Alois P. Heinz, Aug 08 2012

Keywords

Comments

The concatenation of all rows (with offset 1) gives a permutation of the natural numbers A000027 with fixed points 1-6, 9, 10, 14, 15, 21, 22, 33, 49, 1095199, ... and inverse permutation A215501.
Number m is positioned in row n = A056239(m). The number of different values m, such that both m and m+1 occur in row n is A088850(n). A215369 lists all values m, such that both m and m+1 are in the same row.
The power prime(i)^j of the i-th prime is in row i*j for j in {0,1,2, ... }.
Column k=2 contains the even semiprimes A100484, where 10 and 22 are replaced by the odd semiprimes 9 and 21, respectively.
This triangle is related to the triangle A145518, see in both triangles the first column, the right border, the second right border and the row sums. - Omar E. Pol, May 18 2015

Examples

			The partitions of n=3 are {[3], [2,1], [1,1,1]}, encodings give {prime(3), prime(2)*prime(1), prime(1)^3} = {5, 3*2, 2^3} => row 3 = [5, 6, 8].
For n=0 the empty partition [] gives the empty product 1.
Triangle T(n,k) begins:
   1;
   2;
   3,  4;
   5,  6,  8;
   7,  9, 10, 12, 16;
  11, 14, 15, 18, 20, 24, 32;
  13, 21, 22, 25, 27, 28, 30, 36, 40, 48, 64;
  17, 26, 33, 35, 42, 44, 45, 50, 54, 56, 60, 72, 80, 96, 128;
  ...
Corresponding triangle of integer partitions begins:
  ();
  1;
  2, 11;
  3, 21, 111;
  4, 22, 31, 211, 1111;
  5, 41, 32, 221, 311, 2111, 11111;
  6, 42, 51, 33, 222, 411, 321, 2211, 3111, 21111, 111111;
  7, 61, 52, 43, 421, 511, 322, 331, 2221, 4111, 3211, 22111, 31111, 211111, 1111111;  - _Gus Wiseman_, Dec 12 2016
		

Crossrefs

Column k=1 gives: A008578(n+1).
Last elements of rows give: A000079.
Second to last elements of rows give: A007283(n-2) for n>1.
Row sums give: A145519.
Row lengths are: A000041.
Cf. A129129 (with row elements using order of A080577).
LCM of terms in row n gives A138534(n).
Cf. A112798, A246867 (the same for partitions into distinct parts).

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0 or i<2, [2^n],
           [seq(map(p->p*ithprime(i)^j, b(n-i*j, i-1))[], j=0..n/i)])
        end:
    T:= n-> sort(b(n, n))[]:
    seq(T(n), n=0..10);
    # (2nd Maple program)
    with(combinat): A := proc (n) local P, A, i: P := partition(n): A := {}; for i to nops(P) do A := `union`(A, {mul(ithprime(P[i][j]), j = 1 .. nops(P[i]))}) end do: A end proc; # the command A(m) yields row m. # Emeric Deutsch, Jan 23 2016
    # (3rd Maple program)
    q:= 7: S[0] := {1}: for m to q do S[m] := `union`(seq(map(proc (f) options operator, arrow: ithprime(j)*f end proc, S[m-j]), j = 1 .. m)) end do; # for a given positive integer q, the program yields rows 0, 1, 2,...,q. # Emeric Deutsch, Jan 23 2016
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0 || i<2, {2^n}, Table[Function[#*Prime[i]^j] /@ b[n - i*j, i-1], {j, 0, n/i}] // Flatten]; T[n_] := Sort[b[n, n]]; Table[T[n], {n, 0, 10}] // Flatten (* Jean-François Alcover, Mar 12 2015, after Alois P. Heinz *)
    nn=7;HeinzPartition[n_]:=If[n===1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]//Reverse];
    Take[GatherBy[Range[2^nn],Composition[Total,HeinzPartition]],nn+1] (* Gus Wiseman, Dec 12 2016 *)
    Table[Map[Times @@ Prime@ # &, IntegerPartitions[n]], {n, 0, 8}] // Flatten (* Michael De Vlieger, Jul 12 2017 *)
  • PARI
    \\ From M. F. Hasler, Dec 06 2016 (Start)
    A215366_row(n)=vecsort([vecprod([prime(p)|p<-P])|P<-partitions(n)]) \\ bug fix & syntax update by M. F. Hasler, Oct 20 2023
    A215366_vec(N)=concat(apply(A215366_row,[0..N])) \\ "flattened" rows 0..N (End)

Formula

Recurrence relation, explained for the set S(4) of entries in row 4: multiply the entries of S(3) by 2 (= 1st prime), multiply the entries of S(2) by 3 (= 2nd prime), multiply the entries of S(1) by 5 (= 3rd prime), multiply the entries of S(0) by 7 (= 4th prime); take the union of all the obtained products. The 3rd Maple program is based on this recurrence relation. - Emeric Deutsch, Jan 23 2016

A036036 Triangle read by rows in which row n lists all the parts of all reversed partitions of n, sorted first by length and then lexicographically.

Original entry on oeis.org

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

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Author

Keywords

Comments

First differs from A334442 for reversed partitions of 9. Namely, this sequence has (1,4,4) before (2,2,5), while A334442 has (2,2,5) before (1,4,4). - Gus Wiseman, May 07 2020
This is the "Abramowitz and Stegun" ordering of the partitions, referenced in numerous other sequences. The partitions are in reverse order of the conjugates of the partitions in Mathematica order (A080577). Each partition is the conjugate of the corresponding partition in Maple order (A080576). - Franklin T. Adams-Watters, Oct 18 2006
The "Abramowitz and Stegun" ordering of the partitions is the graded reflected colexicographic ordering of the partitions. - Daniel Forgues, Jan 19 2011
The "Abramowitz and Stegun" ordering of partitions has been traced back to C. F. Hindenburg, 1779, in the Knuth reference, p. 38. See the Hindenburg link, pp. 77-5 with the listing of the partitions for n=10. This is also mentioned in the P. Luschny link. - Wolfdieter Lang, Apr 04 2011
The "Abramowitz and Stegun" order used here means that the partitions of a given number are listed by increasing number of (nonzero) parts, then by increasing lexicographical order with parts in (weakly) indecreasing order. This differs from n=9 on from A334442 which considers reverse lexicographic order of parts in (weakly) decreasing order. - M. F. Hasler, Jul 12 2015, corrected thanks to Gus Wiseman, May 14 2020
This is the Abramowitz-Stegun ordering of reversed partitions (finite weakly increasing sequences of positive integers). The same ordering of non-reversed partitions is A334301. - Gus Wiseman, May 07 2020

Examples

			1
2; 1,1
3; 1,2; 1,1,1
4; 1,3; 2,2; 1,1,2; 1,1,1,1
5; 1,4; 2,3; 1,1,3; 1,2,2; 1,1,1,2; 1,1,1,1,1;
6; 1,5; 2,4; 3,3; 1,1,4; 1,2,3; 2,2,2; 1,1,1,3; 1,1,2,2; 1,1,1,1,2; 1,1,1,1,1,1;
...
		

References

  • Abramowitz and Stegun, Handbook, p. 831, column labeled "pi".
  • D. Knuth, The Art of Computer Programming, Vol. 4, fascicle 3, 7.2.1.4, Addison-Wesley, 2005.

Crossrefs

See A036037 for the graded colexicographic ordering.
See A080576 for the Maple (graded reflected lexicographic) ordering.
See A080577 for the Mathematica (graded reverse lexicographic) ordering.
See A193073 for the graded lexicographic ordering.
See A228100 for the Fenner-Loizou (binary tree) ordering.
The version ignoring length is A026791.
Same as A036037 with partitions reversed.
The lengths of these partitions are A036043.
The number of distinct parts is A103921.
The corresponding ordering of compositions is A124734.
Showing partitions as Heinz numbers gives A185974.
The version for non-reversed partitions is A334301.
Lexicographically ordered reversed partitions are A026791.
Sorting reversed partitions by Heinz number gives A112798.
The version for revlex instead of lex is A334302.
The version for revlex instead of colex is A334442.

Programs

  • Mathematica
    Join@@Table[Sort[Reverse/@IntegerPartitions[n]],{n,0,8}] (* Gus Wiseman, May 07 2020 *)
    - or -
    colen[f_,c_]:=OrderedQ[{Reverse[f],Reverse[c]}];
    Reverse/@Join@@Table[Sort[IntegerPartitions[n],colen],{n,0,8}] (* Gus Wiseman, May 07 2020 *)
  • PARI
    T036036(n,k)=k&&return(T036036(n)[k]);concat(partitions(n))
    \\ If 2nd arg "k" is not given, return the n-th row as a vector. Assumes PARI version >= 2.7.1. See A193073 for "hand made" code.
    concat(vector(8,n,T036036(n))) \\ to get the "flattened" sequence
    \\ M. F. Hasler, Jul 12 2015

Extensions

Edited by Daniel Forgues, Jan 21 2011
Edited by M. F. Hasler, Jul 12 2015
Name corrected by Gus Wiseman, May 12 2020
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