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.

A328346 Triangle read by rows: T(n,k) is the coefficient of x^(n - k*(k+1)) in Product_{j=1..k} 1/(1 - x^j) for n >= 0, 0 <= k <= A259361(n).

Original entry on oeis.org

1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 2, 0, 1, 2, 0, 1, 3, 0, 1, 3, 0, 1, 4, 1, 0, 1, 4, 1, 0, 1, 5, 2, 0, 1, 5, 3, 0, 1, 6, 4, 0, 1, 6, 5, 0, 1, 7, 7, 0, 1, 7, 8, 0, 1, 8, 10, 1, 0, 1, 8, 12, 1, 0, 1, 9, 14, 2, 0, 1, 9, 16, 3, 0, 1, 10, 19, 5, 0, 1, 10, 21, 6
Offset: 0

Views

Author

Seiichi Manyama, Oct 13 2019

Keywords

Examples

			Triangle begins:
  1;
  0;
  0, 1;
  0, 1;
  0, 1;
  0, 1;
  0, 1, 1;
  0, 1, 1;
  0, 1, 2;
  0, 1, 2;
  0, 1, 3;
  0, 1, 3;
  0, 1, 4,  1;
  0, 1, 4,  1;
  0, 1, 5,  2;
  0, 1, 5,  3;
  0, 1, 6,  4;
  0, 1, 6,  5;
  0, 1, 7,  7;
  0, 1, 7,  8;
  0, 1, 8, 10, 1;
		

Crossrefs

Row sums give A003106.

Programs

  • PARI
    T(n, k) = polcoef(1/prod(j=1, k, 1-x^j+x*O(x^n)), n-k*(k+1));
    tabf(nn) = for(n=0, nn, for(k=0, (-1+sqrt(1+4*n))/2, print1(T(n, k), ", ")); print)