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.

A214403 Triangle, read by rows of terms T(n,k) for k=0..n^2, that starts with a '1' in row 0 with row n>0 consisting of 2*n-1 '1's followed by the partial sums of the prior row.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 3, 4, 6, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 8, 11, 15, 21, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 10, 13, 17, 22, 28, 36, 47, 62, 83, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 19, 24, 30, 37, 45, 55, 68, 85, 107, 135, 171, 218, 280, 363
Offset: 0

Views

Author

Paul D. Hanna, Jul 15 2012

Keywords

Comments

Right border and row sums form A178325.

Examples

			Triangle begins:
  [1];
  [1, 1];
  [1,1,1, 1, 2];
  [1,1,1,1,1, 1,2,3, 4, 6];
  [1,1,1,1,1,1,1, 1,2,3,4,5, 6,8,11, 15, 21];
  [1,1,1,1,1,1,1,1,1, 1,2,3,4,5,6,7, 8,10,13,17,22, 28,36,47, 62, 83];
  ...
Row sums equal the row sums (A178325) of triangle A214398,
where A214398(n, k) = binomial(k^2+n-k-1, n-k):
  1;
  1, 1;
  1, 4, 1;
  1, 10, 9, 1;
  1, 20, 45, 16, 1;
  1, 35, 165, 136, 25, 1;
  1, 56, 495, 816, 325, 36, 1;
  1, 84, 1287, 3876, 2925, 666, 49, 1;
  ...
		

Crossrefs

Programs

  • PARI
    {T(n, k)=if(k>n^2||n<0||k<0, 0, if(n==0,1,if(k<=2*n-1, 1, sum(i=0, k-2*n+1, T(n-1, i)))))}
    for(n=0,10,for(k=0,n^2,print1(T(n,k),", "));print(""))