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 A089471 #6 Mar 30 2012 18:36:39 %S A089471 1,2,9,66,680,9054,147811,2855574,63656423,1607072112,45294892304, %T A089471 1409197189256,47954491442089,1771493331491354,70590010219153189, %U A089471 3017771375030039066,137763757493141082536,6688261925293875095950 %N A089471 Equals the self-convolution of A089470 and also the hyperbinomial transform of A089470. %C A089471 See A088956 for the definition of the hyperbinomial transform. %F A089471 a(n) = sum(k=1, n, A089470(k)*A089470(n-k)); a(n) = sum(k=0, n, (n-k+1)^(n-k-1)*binomial(n, k)*A089470(k)). %e A089471 The self-convolution of A089470 at n=4: a(4) = 680 = 303*1+29*1+4*4+1*29+1*303 and equals the hyperbinomial transform of A089470 at n=4: a(4) = 680 = 125*1+64*1+18*4+4*29+1*303. %Y A089471 Cf. A089470, A088956. %K A089471 nonn %O A089471 0,2 %A A089471 _Paul D. Hanna_, Nov 07 2003