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 A152404 #4 Jun 02 2025 01:14:15 %S A152404 1,4,22,152,1251,11869,126987,1508209,19651299,278321523,4253151796, %T A152404 69700149063,1218679465845,22634882689433,444893598200458, %U A152404 9223269744306877,201091581942120957,4598872183673896769 %N A152404 Column 1 of matrix square of triangle A152400; also, column 3 of square array A152405. %C A152404 Matrix powers of triangle T=A152400 satisfy: %C A152404 column k of T^(j+1) = column j of T^(k+1) for all j>=0, k>=0. %Y A152404 Cf. A152400; A127715, A152401, A152402, A152403; A152405. %K A152404 nonn %O A152404 0,2 %A A152404 _Paul D. Hanna_, Dec 05 2008