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 A128514 #9 Jan 25 2020 01:38:49 %S A128514 1,2,1,5,2,1,12,5,2,1,29,12,5,2,1,70,29,12,5,2,1,169,70,29,12,5,2,1, %T A128514 408,169,70,29,12,5,2,1,985,408,169,70,29,12,5,2,1,2378,985,408,169, %U A128514 70,29,12,5,2,1 %N A128514 Triangle, Pell sequence in every column. %C A128514 Row sums = A048739 starting (1, 3, 8, 20, 49, 119, ...). %C A128514 Riordan array (1/(1-2x-x^2), x). - _Philippe Deléham_, Apr 23 2009 %F A128514 A000129 in every column: (1, 2, 5, 12, 29, ...). %e A128514 First few rows of the triangle: %e A128514 1; %e A128514 2, 1; %e A128514 5, 2, 1; %e A128514 12, 5, 2, 1; %e A128514 29, 12, 5, 2, 1; %e A128514 70, 29, 12, 5, 2, 1; %e A128514 ... %Y A128514 Cf. A000129, A048739. %K A128514 nonn,tabl %O A128514 1,2 %A A128514 _Gary W. Adamson_, Mar 05 2007