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 A111965 #4 Mar 30 2012 18:59:12
%S A111965 1,3,1,11,6,1,45,31,9,1,195,156,60,12,1,873,781,360,98,15,1,3989,3906,
%T A111965 2055,684,145,18,1,18483,19531,11403,4395,1155,201,21,1,86515,97656,
%U A111965 62132,26856,8260,1800,266,24,1,408105,488281,334260,158692,55188,14190
%N A111965 Riordan array (1/sqrt(1-6x+5x^2),x/(1-6x+5x^2)).
%C A111965 Row sums are A111966. Factors as (1/(1-x),x/(1-x))*(1/sqrt(1-4x),x/sqrt(1-4x)).
%F A111965 Number triangle T(n, k)=sum{j=0..n, C((k+2j-1)/2, j)C(j, n-j-k)(-6)^(k-n+2j)5^(n-k-j)}
%e A111965 1;
%e A111965 3,1;
%e A111965 11,6,1;
%e A111965 45,31,9,1;
%e A111965 195,156,60,12,1;
%e A111965 873,781,360,98,15,1;
%K A111965 easy,nonn,tabl
%O A111965 0,2
%A A111965 _Paul Barry_, Aug 23 2005