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 A157597 #4 Mar 31 2012 12:35:25
%S A157597 1,9,630,48670,4293525,358348053,32224041500,2966406894648,
%T A157597 259556693304825,20157653282906667,1439903350550159550,
%U A157597 97064374251531230622,6271845201623139087495,391742584864070048279685
%N A157597 Half the number of length n integer sequences with sum zero and sum of squares 8450.
%H A157597 R. H. Hardin, <a href="/A157597/b157597.txt">Table of n, a(n) for n=2..50</a>
%F A157597 [cache enabling] count(n,s,ss)->count(n,t,tt) where t=s mod n, q=(t-s)/n, tt=ss+2*q*s+n*q^2; count(n,t,tt)=sum[i^2<=tt]{ count(n-1,t-i,tt-i^2) }. a(n)=count(n,0,8450)/2.
%K A157597 nonn
%O A157597 2,2
%A A157597 _R. H. Hardin_ Mar 02 2009