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 A172382 #2 Mar 30 2012 18:59:26 %S A172382 1,0,1,1,3,8,25,84,301,1139,4528,18849,81968,371622,1753164,8589608, %T A172382 43624741,229255133,1244544545,6968765313,40195073827,238527741350, %U A172382 1454722738679,9108812009826,58503226812174,385086101416594 %N A172382 Diagonal sums of number triangle A172380. %C A172382 a(n+2) gives the diagonal sums of A172381. %K A172382 nonn %O A172382 0,5 %A A172382 _Paul Barry_, Feb 01 2010