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 A135387 #7 Jun 05 2021 01:47:03 %S A135387 2,1,2,0,1,2,0,0,1,2,0,0,0,1,2,0,0,0,0,1,2,0,0,0,0,0,1,2,0,0,0,0,0,0, %T A135387 1,2,0,0,0,0,0,0,0,1,2 %N A135387 Triangle read by rows, with (2, 1, 0, 0, 0, ...) in every column. %C A135387 Let the triangle = M, then M^n * [1, 1, 0, 0, 0, ...] generates rows of triangle A118800. M^n * [1, 0, 0, 0, ...] generates rows of triangle A038207. %C A135387 Eigensequence of the triangle = the Pell numbers, A000129: (1, 2, 5, 12, 29, ...). - _Gary W. Adamson_, Dec 29 2008 %F A135387 Triangle by columns (2, 1, 0, 0, 0, 0, 0, ...) in every column. By rows, (n-2) zeros followed by 1, 2. %e A135387 First few rows of the triangle: %e A135387 2; %e A135387 1, 2 %e A135387 0, 1, 2; %e A135387 0, 0, 1, 2; %e A135387 0, 0, 0, 1, 2; %e A135387 0, 0, 0, 0, 1, 2; %e A135387 ... %Y A135387 Cf. A118800, A038207. %Y A135387 Cf. A000129. - _Gary W. Adamson_, Dec 29 2008 %K A135387 nonn,tabl %O A135387 1,1 %A A135387 _Gary W. Adamson_, Dec 09 2007