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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A364891 Triangle read by rows: T(n,k) = (-1)^(k-1)*Sum_{j=0..k-1} (-1)^j*(p(n - j*(2*j + 1)) - p(n - (j + 1)*(2*j + 1))), where p(n) = A000041(n) is the number of partitions of n, and 1 <= k <= n.

Original entry on oeis.org

0, 1, -1, 1, 0, 0, 2, -1, 1, -1, 2, 0, 0, 0, 0, 4, -2, 2, -2, 2, -2, 4, 0, 0, 0, 0, 0, 0, 7, -2, 2, -2, 2, -2, 2, -2, 8, 0, 0, 0, 0, 0, 0, 0, 0, 12, -2, 3, -3, 3, -3, 3, -3, 3, -3, 14, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 21, -2, 4, -4, 4, -4, 4, -4, 4, -4, 4, -4
Offset: 1

Views

Author

Stefano Spezia, Aug 12 2023

Keywords

Examples

			The triangle begins:
   0;
   1, -1;
   1,  0, 0;
   2, -1, 1, -1;
   2,  0, 0,  0, 0;
   4, -2, 2, -2, 2, -2;
   4,  0, 0,  0, 0,  0, 0;
   7, -2, 2, -2, 2, -2, 2, -2;
   8,  0, 0,  0, 0,  0, 0,  0, 0;
  12, -2, 3, -3, 3, -3, 3, -3, 3, -3;
  14,  1, 0,  0, 0,  0, 0,  0, 0,  0, 0;
  ...
		

Crossrefs

Programs

  • Mathematica
    T[n_, k_]:=(-1)^(k-1)*Sum[(-1)^j*(PartitionsP[n-j(2j+1)]-PartitionsP[n-(j+1)(2j+1)]), {j, 0, k-1}]; Flatten[Table[T[n, k], {n, 1, 12}, {k, 1, n}]]

Formula

1st column: T(n,1) = A002865(n) for n > 0.
abs(T(n,n)) = A035457(n).
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