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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A259799 Array read by antidiagonals upwards: T(n,k) = number of partitions of k^n into n-th powers (n>=1, k>=0).

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 2, 3, 1, 1, 2, 4, 5, 1, 1, 2, 5, 8, 7, 1, 1, 2, 7, 17, 19, 11, 1, 1, 2, 9, 36, 62, 43, 15, 1, 1, 2, 13, 88, 253, 258, 98, 22, 1, 1, 2, 19, 218, 1104, 1886, 1050, 220, 30, 1, 1, 2, 27, 550, 5082, 15772, 14800, 4365, 504, 42, 1, 1, 2, 40, 1413, 24119, 140549, 241582, 118238, 18012, 1116, 56
Offset: 1

Views

Author

N. J. A. Sloane, Jul 06 2015

Keywords

Examples

			The array begins:
  1, 1, 2, 3, 5, 7, 11, 15, 22, 30, ...
  1, 1, 2, 4, 8, 19, 43, 98, 220, 504, ...
  1, 1, 2, 5, 17, 62, 258, 1050, 4365, 18012, ...
  1, 1, 2, 7, 36, 253, 1886, 14800, 118238, ...
  1, 1, 2, 9, 88, 1104, 15772, 241582, ...
  ...
		

Crossrefs

T(n,n) gives A331402.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0 or i=1, 1,
          `if`(i=2, 1+iquo(n, i^k), b(n, i-1, k)+
          `if`(i^k>n, 0, b(n-i^k, i, k))))
        end:
    T:= (n, k)-> b(k^n, k, n):
    seq(seq(T(d-k, k), k=0..d-1), d=1..12);  # Alois P. Heinz, Jul 10 2015
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n==0 || i==1, 1, If[i==2, 1+Quotient[n, i^k], b[n, i-1, k] + If[i^k>n, 0, b[n-i^k, i, k]]]]; T[n_, k_] := b[k^n, k, n]; Table[ Table[ T[d-k, k], {k, 0, d-1}], {d, 1, 12}] // Flatten (* Jean-François Alcover, Jul 15 2015, after Alois P. Heinz *)

Extensions

More terms from Alois P. Heinz, Jul 10 2015

A337989 Number of compositions (ordered partitions) of n^n into n-th powers.

Original entry on oeis.org

1, 2, 120, 131204813713122
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 06 2020

Keywords

Comments

The next term is too large to include.

Examples

			a(3) = 120 because 3^3 = 27 and we have [27], [8, 8, 8, 1, 1, 1] (20 permutations), [8, 8, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] (78 permutations), [8, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] (20 permutations), [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] and 1 + 20 + 78 + 20 + 1 = 120.
		

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[1/(1 - Sum[x^(k^n), {k, 1, n}]), {x, 0, n^n}], {n, 1, 4}]

Formula

a(n) = [x^(n^n)] 1 / (1 - Sum_{k>=1} x^(k^n)).
Showing 1-2 of 2 results.