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.

A091603 Matrix inverse of triangle A091602.

Original entry on oeis.org

1, -1, 1, -2, 0, 1, 0, -2, 0, 1, 1, -2, -1, 0, 1, 3, -1, -2, -1, 0, 1, 4, 0, -2, -1, -1, 0, 1, 3, 2, 0, -2, -1, -1, 0, 1, 3, 3, 0, -1, -1, -1, -1, 0, 1, 0, 4, 2, 0, -1, -1, -1, -1, 0, 1, 0, 4, 2, 1, -1, 0, -1, -1, -1, 0, 1, -3, 3, 3, 2, 1, -1, 0, -1, -1, -1, 0, 1, -4, 3, 3, 2, 1, 0, 0, 0, -1, -1, -1, 0, 1
Offset: 1

Views

Author

Christian G. Bower, Jan 23 2004

Keywords

Examples

			Triangle begins as:
   1;
  -1,  1;
  -2,  0,  1;
   0, -2,  0,  1;
   1, -2, -1,  0,  1;
   3, -1, -2, -1,  0,  1;
   4,  0, -2, -1, -1,  0,  1;
   3,  2,  0, -2, -1, -1,  0,  1;
   3,  3,  0, -1, -1, -1, -1,  0,  1;
   0,  4,  2,  0, -1, -1, -1, -1,  0,  1;
   0,  4,  2,  1, -1,  0, -1, -1, -1,  0,  1;
  -3,  3,  3,  2,  1, -1,  0, -1, -1, -1,  0,  1;
  -4,  3,  3,  2,  1,  0,  0,  0, -1, -1, -1,  0,  1;
  -7,  2,  3,  2,  2,  1,  0,  0,  0, -1, -1, -1,  0,  1;
  -9,  1,  3,  2,  2,  1,  0,  1,  0,  0, -1, -1, -1,  0,  1;
		

Crossrefs

Cf. A091602, A091612 (column 1).

Programs

  • Mathematica
    b[n_, i_, k_]:= b[n, i, k]= If[n==0, 1, If[i>n, 0, Sum[b[n-i*j, i+1, Min[k, Quotient[n-i*j, i+1]]], {j,0,k}]]];
    t[n_, k_]:= t[n, k]= b[n, 1, k] - b[n, 1, k-1]; (* t = A091602 *)
    M:= With[{p = 30}, Table[t[n, k], {n, p}, {k, p}]];
    T:= Inverse[M];
    Table[T[[n, k]], {n, 15}, {k, n}]//Flatten (* G. C. Greubel, Nov 26 2021 *)