%I #14 Oct 30 2021 09:42:46
%S 1,1,13,91,1081,10606,181189,2025325,38378449,548523856,10811257051,
%T 176339404099,3828413138785,68734868302738,1590128353317001,
%U 31543123841374681,768191679788034529,16494997547298477340
%N a(n) = Sum_{i+j+k=n, 0<=i<=j<=k<=n} (n+2j)!/(i! * (3j)! * k!).
%H Vaclav Kotesovec, <a href="/A092469/b092469.txt">Table of n, a(n) for n = 0..500</a> (terms 0..200 from Seiichi Manyama)
%o (PARI) a(n)=sum(i=0,n,sum(j=0,i,sum(k=0,j,if(i+j+k-n,0,(n+2*j)!/i!/(2*j)!/k!))))
%Y Cf. A092468.
%K nonn
%O 0,3
%A _Benoit Cloitre_, Mar 25 2004