%I #7 Apr 23 2022 16:21:11
%S 1,1,3,4,9,14,31,53,117,215,478,930,2092,4266,9732,20645,47820,104941,
%T 246931,558190,1334462,3097018,7521731,17874931,44092014
%N Antidiagonal sums of triangle A183202.
%o (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))))}
%o {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)))}
%o {a(n)=sum(k=0,n,A183202(n-k,k))}
%Y Cf. A183202.
%K more,nonn
%O 0,3
%A _Paul D. Hanna_, Dec 30 2010