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.

Showing 1-5 of 5 results.

A238016 Number A(n,k) of partitions of n^k into parts that are at most n; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

0, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 3, 1, 1, 1, 5, 12, 5, 1, 1, 1, 9, 75, 64, 7, 1, 1, 1, 17, 588, 2280, 377, 11, 1, 1, 1, 33, 5043, 123464, 106852, 2432, 15, 1, 1, 1, 65, 44652, 7566280, 55567352, 6889527, 16475, 22, 1
Offset: 0

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Author

Alois P. Heinz, Feb 17 2014

Keywords

Comments

In general, for k>3, is column k asymptotic to exp(2*n) * n^((k-2)*n-k) / (2*Pi). For k=1 see A000041, for k=2 see A206226 and for k=3 see A238608. - Vaclav Kotesovec, May 25 2015
Conjecture: If f(n) >= O(n^4) then "number of partitions of f(n) into parts that are at most n" is asymptotic to f(n)^(n-1) / (n!*(n-1)!). See also A237998, A238000, A236810 or A258668-A258672. - Vaclav Kotesovec, Jun 07 2015

Examples

			A(3,1) = 3: 3, 21, 111.
A(3,2) = 12: 333, 3222, 3321, 22221, 32211, 33111, 222111, 321111, 2211111, 3111111, 21111111, 111111111.
A(2,3) = 5: 2222, 22211, 221111, 2111111, 11111111.
A(2,4) = 9: 22222222, 222222211, 2222221111, 22222111111, 222211111111, 2221111111111, 22111111111111, 211111111111111, 1111111111111111.
Square array A(n,k) begins:
  0, 1,   1,      1,        1,           1, ...
  1, 1,   1,      1,        1,           1, ...
  1, 2,   3,      5,        9,          17, ...
  1, 3,  12,     75,      588,        5043, ...
  1, 5,  64,   2280,   123464,     7566280, ...
  1, 7, 377, 106852, 55567352, 33432635477, ...
		

Crossrefs

Programs

  • Mathematica
    A[n_, k_] := SeriesCoefficient[Product[1/(1-x^j), {j, 1, n}], {x, 0, n^k}]; A[0, 0] = 0; Table[A[n-k, k], {n, 0, 10}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Oct 11 2015 *)

Formula

A(n,k) = [x^(n^k)] Product_{j=1..n} 1/(1-x^j).

A236810 Number of solutions to Sum_{k=1..n} k*c(k) = n! , c(k) >= 0.

Original entry on oeis.org

0, 1, 2, 7, 169, 91606, 2407275335, 4592460368601183, 855163933625625205568537, 20560615981766266405801870502139241, 82864945825700191674729490954631752385038099201, 70899311833745096407560015806403481692583415598602691709750081
Offset: 0

Views

Author

Wouter Meeussen, Feb 08 2014

Keywords

Comments

a(n) is the number of partitions of n! into parts that are at most n. a(3) = 7: [1,1,1,1,1,1], [2,1,1,1,1], [2,2,1,1], [2,2,2], [3,1,1,1], [3,2,1], [3,3]. - Alois P. Heinz, Feb 08 2014

Examples

			for n=3, the 7 solutions are: 3! = 6,0,0 ; 4,1,0 ; 2,2,0 ; 0,3,0 ; 3,0,1 ; 1,1,1 ; 0,0,2.
		

Crossrefs

Programs

  • Mathematica
    Table[Coefficient[Series[Product[1/(1- x^k),{k,n}],{x,0,n!}],x^(n!)] ,{n,7}]

Formula

a(n) = [x^(n!)] Product_{k=1..n} 1/(1-x^k).
a(n) ~ n * (n!)^(n-3) ~ n^(n^2-5*n/2-1/2) * (2*Pi)^((n-3)/2) / exp(n*(n-3)-1/12). - Vaclav Kotesovec, Jun 05 2015

Extensions

a(8)-a(11) from Alois P. Heinz, Feb 08 2014

A258669 Number of partitions of 2*n! into parts that are at most n.

Original entry on oeis.org

0, 1, 3, 19, 1033, 1302311, 74312057469, 291484874476601933, 109290159404495354765494065, 5262212497884462986538879797523944401, 42425405450182072688801993326226988336684453926401, 72600595215718916449806606426629386781199080157371905867835756161
Offset: 0

Views

Author

Vaclav Kotesovec, Jun 07 2015

Keywords

Crossrefs

Formula

a(n) ~ n * 2^(n-1) * (n!)^(n-3).

A258670 Number of partitions of (2*n)! into parts that are at most n.

Original entry on oeis.org

0, 1, 13, 43561, 455366036161, 60209252317216962943201, 291857679749953126623181556402787323521, 120972618144269517756284629487432992029777542693069847287041
Offset: 0

Views

Author

Vaclav Kotesovec, Jun 07 2015

Keywords

Comments

Conjecture: If f(n) >= O(n^4) then "number of partitions of f(n) into parts that are at most n" is asymptotic to f(n)^(n-1) / (n!*(n-1)!). For the examples see A238016 and A238010.

Crossrefs

Formula

a(n) ~ (2*n)!^(n-1) / (n!*(n-1)!).

A258671 Number of partitions of (n!)^2 into parts that are at most n.

Original entry on oeis.org

0, 1, 3, 127, 1361953, 14961046326601, 433366367372593816560481, 74029504174329565838647515081008812321, 147684970947386323832216294475743896349724799651361817601
Offset: 0

Views

Author

Vaclav Kotesovec, Jun 07 2015

Keywords

Crossrefs

Formula

a(n) ~ n * (n!)^(2*n-4).
Showing 1-5 of 5 results.