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.
%I A132428 #13 Nov 11 2024 01:58:27
%S A132428 1,1,3,10,43,216,1241,7988,56763,440254,3693728,33281359,320112326,
%T A132428 3270177860,35329070470,402128329243,4806784533967,60166803598106,
%U A132428 786622663286330,10717555856584617,151864784070048105
%N A132428 Central terms of triangle A132427.
%F A132428 Binomial transform equals A125273.
%F A132428 a(n)=sum(k=1..n, sum(i=k..n, binomial(i-1,k-1)*binomial(i,n-i))*a(k-1)), n>0,a(0)=1. [_Vladimir Kruchinin_, May 02 2012]
%o A132428 (PARI) {a(n)=local(G=1+x+x*O(x^n));for(i=0,n,G=1+x*subst(G,x,x/(1-x)^2)/(1-x)); polcoeff(subst((G-1)/x,x,x/(1+x))/(1+x),n)}
%o A132428 (Maxima) a(n):=if n=0 then 1 else sum(sum(binomial(i-1,k-1)*binomial(i,n-i),i,k,n)*a(k-1),k,1,n); /* _Vladimir Kruchinin_, May 02 2012 */
%Y A132428 Cf. A125273; A132427.
%K A132428 nonn,tabl
%O A132428 0,3
%A A132428 _Paul D. Hanna_, Aug 21 2007