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 A152403 #2 Mar 30 2012 18:37:15 %S A152403 1,4,24,182,1636,16844,194384,2476868,34461956,519070980,8405444924, %T A152403 145502477888,2679656009072,52289220500822,1077289873778412, %U A152403 23361106832257087,531744673834247758,12673569230875132668 %N A152403 Column 3 of triangle A152400. %C A152403 Matrix powers of triangle T=A152400 satisfy: %C A152403 column k of T^(j+1) = column j of T^(k+1) for all j>=0, k>=0. %Y A152403 Cf. A152400; A127715, A152401, A152402, A152404; A152405. %K A152403 nonn %O A152403 0,2 %A A152403 _Paul D. Hanna_, Dec 05 2008