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.

A119687 f-Pascal's triangle where f(n) = n^2 = A000290(n).

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 5, 5, 1, 1, 26, 50, 26, 1, 1, 677, 3176, 3176, 677, 1, 1, 458330, 10545305, 20173952, 10545305, 458330, 1, 1, 210066388901, 111413523931925, 518191796841329, 518191796841329, 111413523931925, 210066388901, 1
Offset: 0

Views

Author

Philippe Deléham, Jun 09 2006

Keywords

Comments

The second diagonal, T(n,n-1) = A003095(n). - Cortney Reagle, Sep 17 2019

Examples

			Triangle T(n,k) (with rows n >= 0 and columns 0 <= k <= n) begins as follows:
  1;
  1,      1;
  1,      2,        1;
  1,      5,        5,        1;
  1,     26,       50,       26,        1;
  1,    677,     3176,     3176,      677,      1;
  1, 458330, 10545305, 20173952, 10545305, 458330, 1;
  ...
		

Crossrefs

Row sums are A327563.

Programs

  • PARI
    T(n)={my(M=matrix(n,n)); M[1,1]=1; for(n=2, n, M[n,1]=1; for(k=2, n, M[n,k]=M[n-1,k-1]^2 + M[n-1,k]^2)); M}
    { my(A=T(7)); for(i=1, #A, print(A[i,1..i])) } \\ Andrew Howroyd, Sep 17 2019

Formula

T(n, k) = T(n-1, k-1)^2 + T(n-1, k)^2; T(0,0) = 1; T(n,-1) = 0; T(n, k) = 0, n < k.

Extensions

a(12) = 50 inserted and more terms added by Cortney Reagle, Sep 17 2019