A183203 Antidiagonal sums of triangle A183202.

1, 1, 3, 4, 9, 14, 31, 53, 117, 215, 478, 930, 2092, 4266, 9732, 20645, 47820, 104941, 246931, 558190, 1334462, 3097018, 7521731, 17874931, 44092014

Offset: 0

Author

Paul D. Hanna, Dec 30 2010

Keywords

• more
• nonn

Crossrefs

Cf. A183202.

Programs

PARI

{A131338(n, k)=if(k>n*(n+1)/2||k<0,0,if(k<=n,1,sum(i=0, k-n,A131338(n-1,i))))}
{A183202(n,k)=if(n==k,A131338(n,n*(n+1)/2),sum(j=n*k-k*(k-1)/2,n*k-k*(k-1)/2+n-k-1,A131338(n,j)))}
{a(n)=sum(k=0,n,A183202(n-k,k))}