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.

Previous Showing 11-19 of 19 results.

A376369 Number of nondecreasing tuples (x_1, ..., x_k) of positive integers (or integer partitions) such that the multinomial coefficient (x_1 + ... + x_k)!/(x_1! * ... * x_k!) equals n.

Original entry on oeis.org

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

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Author

Pontus von Brömssen, Sep 22 2024

Keywords

Comments

a(n) is the number of occurrences of n in each of A036038, A050382, A078760, A318762, and A376367.
The sequence is unbounded. To see this, note that the sets of parts (1,1,1,4) and (2,2,3) of a partition can be exchanged without affecting the value of the multinomial coefficient, because 1+1+1+4 = 2+2+3 and 1!*1!*1!*4! = 2!*2!*3!. In particular, a((7*k)!/24^k) >= k+1 from the partitions 7*k = (3*j)*1 + j*4 + (2*(k-j))*2 + (k-j)*3 for 0 <= j <= k.

Examples

			a(6) = 3, because 6 can be written as a multinomial coefficient in 3 ways: 6 = 6!/(1!*5!) = 4!/(2!*2!) = 3!/(1!*1!*1!).
		

Crossrefs

A376367 Sorted multinomial coefficients greater than 1, including duplicates.

Original entry on oeis.org

2, 3, 4, 5, 6, 6, 6, 7, 8, 9, 10, 10, 11, 12, 12, 13, 14, 15, 15, 16, 17, 18, 19, 20, 20, 20, 21, 21, 22, 23, 24, 24, 25, 26, 27, 28, 28, 29, 30, 30, 30, 31, 32, 33, 34, 35, 35, 36, 36, 37, 38, 39, 40, 41, 42, 42, 43, 44, 45, 45, 46, 47, 48, 49, 50, 51, 52, 53
Offset: 1

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Author

Pontus von Brömssen, Sep 22 2024

Keywords

Comments

Sorted terms of A036038, A050382, A078760, or A318762, excluding 1 (which appears infinitely often).
The number k appears A376369(k) times.

Crossrefs

Formula

a(n) = A318762(A376379(n)).

A376661 Frequency of the most common number among the multinomial coefficients n!/(x_1! * ... * x_k!) for all partitions (x_1, ..., x_k) of n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 6, 6, 7, 8, 9, 11, 11, 13, 13, 14, 15, 16, 18, 19, 20, 23, 24, 26, 27, 30, 33, 37, 40, 43, 49, 52, 57, 64, 68, 76, 79, 87, 93, 99, 109, 116, 125, 135, 143, 157, 171, 191, 206, 223, 238, 254, 276, 291
Offset: 0

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Author

Pontus von Brömssen, Oct 02 2024

Keywords

Comments

Frequency of the most common number in row n of A036038 (for n >= 1) or A078760.
The sequence is nondecreasing, because a set of partitions of n-1 with a common multinomial coefficient can be extended to a set of partitions of n with a common multinomial coefficient by adding a unit part to each partition. It appears that a(n) > a(n-1) for n >= 28.
The sequence is unbounded. To see this, note that the sets of parts (1,1,1,4) and (2,2,3) of a partition can be exchanged without affecting the value of the multinomial coefficient, because 1+1+1+4 = 2+2+3 and 1!*1!*1!*4! = 2!*2!*3!. In particular, a((7*k)!/24^k) >= k+1 from the partitions 7*k = (3*j)*1 + j*4 + (2*(k-j))*2 + (k-j)*3 for 0 <= j <= k.

Examples

			For n = 7, the only number that appears more than once in row 7 of A036038 is 210, which appears twice: 210 = 7!/(2!*2!*3!) = 7!/(1!*1!*1!*4!). Hence, a(7) = 2.
		

Crossrefs

A210237 Triangle of distinct values M(n) of multinomial coefficients for partitions of n in increasing order of n and M(n).

Original entry on oeis.org

1, 1, 2, 1, 3, 6, 1, 4, 6, 12, 24, 1, 5, 10, 20, 30, 60, 120, 1, 6, 15, 20, 30, 60, 90, 120, 180, 360, 720, 1, 7, 21, 35, 42, 105, 140, 210, 420, 630, 840, 1260, 2520, 5040, 1, 8, 28, 56, 70, 168, 280, 336, 420, 560, 840, 1120, 1680, 2520, 3360, 5040, 6720
Offset: 1

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Author

Sergei Viznyuk, Mar 18 2012

Keywords

Comments

Differs from A036038 after a(37). To illustrate where the difference comes from, consider 4,1,1,1 and 3,2,2 are two different partitions of 7 having the same value of multinomial coefficient M(n)=n!/(m1!*m2!*...*mk!)=210.
There is no known formula for M(n) sequence, however the asymptotic behavior has been studied, see the paper by Andrews, Knopfmacher, and Zimmermann.
The number of terms per row (for each value of n starting with n=1) forms sequence A070289.

Examples

			Trianglebegins:
  1;
  1, 2;
  1, 3,  6;
  1, 4,  6, 12, 24;
  1, 5, 10, 20, 30,  60, 120;
  1, 6, 15, 20, 30,  60,  90, 120, 180, 360, 720;
  1, 7, 21, 35, 42, 105, 140, 210, 420, 630, 840, 1260, 2520, 5040;
  ...
Thus for n=4 (fourth row) the distinct values of multinomial coefficients are:
  4!/(4!) = 1
  4!/(3!1!) = 4
  4!/(2!2!) = 6
  4!/(2!1!1!) = 12
  4!/(1!1!1!1!) = 24
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0 or i<2, {1},
          {seq(map(x-> x*i!^j, b(n-i*j, i-1))[], j=0..n/i)})
        end:
    T:= n-> sort([map(x-> n!/x, b(n, n))[]])[]:
    seq(T(n), n=1..10);  # Alois P. Heinz, Aug 13 2012
  • Mathematica
    b[n_, i_] := b[n, i] = If[n==0 || i<2, {1}, Union[Flatten @ Table[(#*i!^j&) /@ b[n-i*j, i-1], {j, 0, n/i}]]]; T[n_] := Sort[Flatten[n!/#& /@ b[n, n]] ]; Table[T[n], {n, 1, 10}] // Flatten (* Jean-François Alcover, Feb 05 2017, after Alois P. Heinz *)

A309972 Product of multinomial coefficients M(n;lambda), where lambda ranges over all partitions of n.

Original entry on oeis.org

1, 1, 2, 18, 6912, 216000000, 1632586752000000000, 498266101635303733401600000000000, 1140494258799407218656986754465090350453096448000000000000000
Offset: 0

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Author

Alois P. Heinz, Aug 25 2019

Keywords

Examples

			a(3) = M(3;3) * M(3;2,1) * M(3;1,1,1) = 1 * 3 * 6 = 18.
		

Crossrefs

Rightmost terms in rows of A309951.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0 or i=1, [n!], [map(t->
          binomial(n, i)*t, b(n-i, min(n-i, i)))[], b(n, i-1)[]])
        end:
    a:= n-> mul(i, i=b(n$2)):
    seq(a(n), n=0..9);  # Alois P. Heinz, Aug 25 2019
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0 || i == 1, {n!}, Join[Binomial[n, i] #& /@ b[n - i, Min[n - i, i]], b[n, i - 1]]];
    a[n_] := Times @@ b[n, n];
    a /@ Range[0, 9] (* Jean-François Alcover, Dec 07 2020, after Alois P. Heinz *)

Formula

a(n) = Product_{k=1..A000041(n)} A036038(n,k).
a(n) = A309951(n,A000041(n)).

A376368 Least number k with a partition k = x_1 + ... + x_j such that the multinomial coefficient k!/(x_1! * ... * x_j!) is equal to n.

Original entry on oeis.org

0, 2, 3, 4, 5, 3, 7, 8, 9, 5, 11, 4, 13, 14, 6, 16, 17, 18, 19, 5, 7, 22, 23, 4, 25, 26, 27, 8, 29, 5, 31, 32, 33, 34, 7, 9, 37, 38, 39, 40, 41, 7, 43, 44, 10, 46, 47, 48, 49, 50, 51, 52, 53, 54, 11, 8, 57, 58, 59, 5, 61, 62, 63, 64, 65, 12, 67, 68, 69, 8, 71
Offset: 1

Views

Author

Pontus von Brömssen, Sep 22 2024

Keywords

Comments

Index of first row of A078760 (or A036038 when n >= 2) that contains n.
a(n) <= n, with equality if and only if n is in A376371, i.e., if and only if n is not in A325472.

Examples

			a(6) = 3, because 6 appears in row 3 of A078760, corresponding to the multinomial coefficient 3!/(1!*1!*1!) = 6.
		

Crossrefs

Formula

a(k!) = k for k != 1.

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 *)

A249619 Triangle T(m,n) = number of permutations of a multiset with m elements and signature corresponding to n-th integer partition (A194602).

Original entry on oeis.org

1, 1, 2, 1, 6, 3, 1, 24, 12, 4, 6, 1, 120, 60, 20, 30, 5, 10, 1, 720, 360, 120, 180, 30, 60, 6, 90, 15, 20, 1, 5040, 2520, 840, 1260, 210, 420, 42, 630, 105, 140, 7, 210, 21, 35, 1, 40320, 20160, 6720, 10080, 1680, 3360, 336, 5040, 840, 1120, 56
Offset: 0

Views

Author

Tilman Piesk, Nov 04 2014

Keywords

Comments

This triangle shows the same numbers in each row as A036038 and A078760 (the multinomial coefficients), but in this arrangement the multisets in column n correspond to the n-th integer partition in the infinite order defined by A194602.
Row lengths: A000041 (partition numbers), Row sums: A005651
Columns: 0: A000142 (factorials), 1: A001710, 2: A001715, 3: A133799, 4: A001720, 6: A001725, 10: A001730, 14: A049388
Last in row: end-2: A037955 after 1 term mismatch, end-1: A001405, end: A000012
The rightmost columns form the triangle A173333:
n 0 1 2 4 6 10 14 21 (A000041(1,2,3...)-1)
m
1 1
2 2 1
3 6 3 1
4 24 12 4 1
5 120 60 20 5 1
6 720 360 120 30 6 1
7 5040 2520 840 210 42 7 1
8 40320 20160 6720 1680 336 56 8 1
A249620 shows the number of partitions of the same multisets. A187783 shows the number of permutations of special multisets.

Examples

			Triangle begins:
  n     0    1    2    3   4   5  6   7   8   9 10
m
0       1
1       1
2       2    1
3       6    3    1
4      24   12    4    6   1
5     120   60   20   30   5  10  1
6     720  360  120  180  30  60  6  90  15  20  1
		

Crossrefs

A376662 The smallest of the most common numbers among the multinomial coefficients n!/(x_1! * ... * x_k!) for all partitions (x_1, ..., x_k) of n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 210, 56, 504, 1260, 9240, 166320, 360360, 5045040, 75675600, 1210809600, 4084080, 73513440, 698377680, 13967553600, 146659312800, 1075501627200, 37104806138400, 296838449107200, 7420961227680000, 96472495959840000, 2604757390915680000
Offset: 0

Views

Author

Pontus von Brömssen, Oct 02 2024

Keywords

Comments

a(n) is the smallest number that appears A376661(n) times in row n of A036038 (for n >= 1) or A078760.

Examples

			For n = 8, the only numbers that appear more than once in row 8 of A036038 are 56 and 1680, which both appear twice. Since 56 < 1680, a(8) = 56.
		

Crossrefs

Previous Showing 11-19 of 19 results.