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 A102427 #7 Aug 03 2013 07:25:23 %S A102427 1,1,1,1,3,2,1,5,4,1,1,7,6,6,3,1,9,8,15,10,1,1,11,10,28,21,10,4,1,13, %T A102427 12,45,36,35,20,1,1,15,14,66,55,84,56,15,5,1,17,16,91,78,165,120,70, %U A102427 35,1,1,19,18,120,105,286,220,210,126,21,6 %N A102427 Triangle based on downward diagonals of A102426. %F A102427 T(n, k)=if(k<=n, binomial(floor((2n-k+2)/2)+n-k, floor((2n-k+1)/2)-n+k), 0) - _Paul Barry_, Jun 22 2005 %Y A102427 Cf. A011973, A102426, A102428, A102429. %K A102427 easy,nonn,tabl %O A102427 0,5 %A A102427 _Russell Walsmith_, Jan 11 2005 %E A102427 Corrected and extended by _Paul Barry_, Jun 22 2005