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.

A255212 Number A(n,k) of partitions of n^2 into at most k square parts; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

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

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Author

Alois P. Heinz, Feb 17 2015

Keywords

Examples

			Square array A(n,k) begins:
  1, 1, 1, 1, 1,  1,  1,  1,  1,  1,  1, ...
  0, 1, 1, 1, 1,  1,  1,  1,  1,  1,  1, ...
  0, 1, 1, 1, 2,  2,  2,  2,  2,  2,  2, ...
  0, 1, 1, 2, 2,  2,  3,  3,  3,  4,  4, ...
  0, 1, 1, 1, 2,  3,  3,  4,  5,  5,  6, ...
  0, 1, 2, 2, 3,  4,  5,  7,  8,  9, 11, ...
  0, 1, 1, 2, 4,  5,  9, 10, 11, 15, 17, ...
  0, 1, 1, 2, 4,  6,  9, 13, 18, 21, 27, ...
  0, 1, 1, 1, 2,  7,  9, 16, 25, 30, 41, ...
  0, 1, 1, 4, 6,  8, 18, 27, 36, 52, 68, ...
  0, 1, 2, 2, 7, 13, 23, 36, 51, 70, 94, ...
		

Crossrefs

Main diagonal gives A105152.
Cf. A302996.

Programs

  • Maple
    b:= proc(n, i, t) option remember; `if`(n=0 or i=1 and n<=t, 1,
          (j-> `if`(t*jn, 0, b(n-j, i, t-1))))(i^2))
        end:
    A:= (n, k)-> b(n^2, n, k):
    seq(seq(A(n, d-n), n=0..d), d=0..15);
  • Mathematica
    b[n_, i_, t_] := b[n, i, t] = If[n == 0 || i == 1 && n <= t, 1, Function[j, If[t*jn, 0, b[n-j, i, t-1]]]][i^2]]; A[n_, k_] := b[n^2, n, k]; Table[Table[A[n, d - n], {n, 0, d}], {d, 0, 15}] // Flatten (* Jean-François Alcover, Feb 22 2016, after Alois P. Heinz *)

A307738 Number of partitions of n^3 into at most n cubes.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 3, 4, 7, 18, 36, 66, 157, 329, 728, 1611, 3655, 8062, 18154, 40358, 89807, 199778, 444419, 984422, 2183461, 4827756, 10651083, 23465459, 51576034, 113092423, 247546849, 540538832, 1177836149, 2560897979, 5555722749, 12025952101, 25976048200
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 25 2019

Keywords

Comments

Does a(n+1) / a(n) ~ 2? - David A. Corneth, Sep 27 2019

Examples

			7^3 =
1^3 + 1^3 + 5^3 + 6^3 =
1^3 + 1^3 + 3^3 + 4^3 + 5^3 + 5^3 =
1^3 + 2^3 + 3^3 + 3^3 + 4^3 + 6^3,
so a(7) = 4.
		

Crossrefs

Programs

  • PARI
    a(n) = {my(res = 0); res=aIterate(n^3, 1, n); res }
    aIterate(s, m, q) = { if(s == 0, return(1)); if(q == 0, return(0)); sum(i = m, sqrtnint(s, 3), aIterate(s - i^3, i, q-1) ) } \\ David A. Corneth, Sep 23 2019

Extensions

a(21)-a(36) from David A. Corneth, Sep 23 2019

A331884 Number of compositions (ordered partitions) of n^2 into distinct squares.

Original entry on oeis.org

1, 1, 1, 1, 1, 3, 1, 7, 1, 31, 123, 151, 121, 897, 7351, 5415, 14881, 48705, 150583, 468973, 1013163, 1432471, 1730023, 50432107, 14925241, 125269841, 74592537, 241763479, 213156871, 895153173, 7716880623, 2681163865, 3190865761, 22501985413, 116279718801
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 30 2020

Keywords

Examples

			a(5) = 3 because we have [25], [16, 9] and [9, 16].
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i, p) option remember;
          `if`(i*(i+1)*(2*i+1)/6n, 0, b(n-i^2, i-1, p+1))+b(n, i-1, p)))
        end:
    a:= n-> b(n^2, n, 0):
    seq(a(n), n=0..35);  # Alois P. Heinz, Jan 30 2020
  • Mathematica
    b[n_, i_, p_] := b[n, i, p] = If[i(i+1)(2i+1)/6 < n, 0, If[n == 0, p!, If[i^2 > n, 0, b[n - i^2, i - 1, p + 1]] + b[n, i - 1, p]]];
    a[n_] := b[n^2, n, 0];
    a /@ Range[0, 35] (* Jean-François Alcover, Nov 08 2020, after Alois P. Heinz *)

Formula

a(n) = A331844(A000290(n)).

Extensions

a(24)-a(34) from Alois P. Heinz, Jan 30 2020

A307739 Number of partitions of n^4 into at most n fourth powers.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 2, 2, 1, 5, 3, 5, 2, 27, 4, 78, 14, 152, 551, 1331, 7377, 15504, 87583, 190028, 768864, 1510305, 5413291, 12221733
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 25 2019

Keywords

Examples

			10^4 =
4^4 + 4^4 + 6^4 + 8^4 + 8^4 =
2^4 + 4^4 + 4^4 + 4^4 + 4^4 + 4^4 + 4^4 + 4^4 + 8^4 + 8^4,
so a(10) = 3.
		

Crossrefs

Programs

  • Python
    from sympy.solvers.diophantine.diophantine import power_representation
    def a(n):
        if n < 2: return 1
        return sum(len(list(power_representation(n**4, 4, j))) for j in range(1, n+1))
    print([a(n) for n in range(1, 20)]) # Michael S. Branicky, Jul 09 2024

Extensions

a(21)-a(27) from Michael S. Branicky, Jul 09 2024

A347590 Number of compositions (ordered partitions) of n^2 into at most n squares.

Original entry on oeis.org

1, 1, 1, 4, 2, 20, 188, 1031, 8777, 62528, 437160, 4185739, 38642386, 383969125, 4149154916, 45160025119, 514181220266, 6133093344169, 75135177511922, 962729735639323, 12745694628358530, 173304634479902187, 2433186864257121180, 35030916937968941062
Offset: 0

Views

Author

Ilya Gutkovskiy, Sep 08 2021

Keywords

Crossrefs

Showing 1-5 of 5 results.