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 A109221 #3 Mar 30 2012 18:59:08 %S A109221 1,1,1,1,1,1,1,1,3,1,1,1,5,3,1,1,1,7,5,6,1,1,1,9,7,15,6,1,1,1,11,9,28, %T A109221 15,10,1,1,1,13,11,45,28,35,10,1,1,1,15,13,66,45,84,35,15,1,1,1,17,15, %U A109221 91,66,165,84,70,15,1,1,1,19,17,120,91,286,165,210,70,21,1,1,1,21,19 %N A109221 A number triangle related to the Fibonacci polynomials. %C A109221 The repeated columns are made up by taking every second element of columns in A011973. Row sums are A109222. %F A109221 Number triangle T(n, k)=binomial(floor((2n-k)/2)+n-k, 2n-2k) %e A109221 Rows begin %e A109221 1; %e A109221 1,1; %e A109221 1,1,1; %e A109221 1,1,3,1; %e A109221 1,1,5,3,1; %e A109221 1,1,7,5,6,1; %K A109221 easy,nonn,tabl %O A109221 0,9 %A A109221 _Paul Barry_, Jun 22 2005