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 A115263 #3 Mar 30 2012 18:59:13
%S A115263 1,1,1,2,2,2,2,3,3,2,3,4,6,4,3,3,5,7,7,5,3,4,6,10,10,10,6,4,4,7,11,13,
%T A115263 13,11,7,4,5,8,14,16,19,16,14,8,5,5,9,15,19,22,22,19,15,9,5,6,10,18,
%U A115263 22,28,28,28,22,18,10,6
%N A115263 Correlation triangle for floor((n+2)/2).
%C A115263 Row sums are A096338. Diagonal sums are A115264. T(2n,n) is A005993. T(2n,n)-T(2n,n+1) is floor((n+2)/2)(1+(-1)^n)/2 (aerated n+1).
%F A115263 G.f.: (1+x)(1+xy)/((1-x^2)^2*(1-x^2*y^2)^2*(1-x^2*y)); Number triangle T(n, k)=sum{j=0..n, [j<=k]*floor((k-j+2)/2)*[j<=n-k]*floor((n-k-j+2)/2)}.
%e A115263 Triangle begins
%e A115263 1;
%e A115263 1,1;
%e A115263 2,2,2;
%e A115263 2,3,3,2;
%e A115263 3,4,6,4,3;
%e A115263 3,5,7,7,5,3;
%K A115263 easy,nonn,tabl
%O A115263 0,4
%A A115263 _Paul Barry_, Jan 18 2006