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 A134560 #16 Oct 28 2023 15:28:33 %S A134560 1,1,3,1,0,5,1,3,0,7,1,0,0,0,9,1,3,5,0,0,11,1,0,0,0,0,0,13,1,3,0,7,0, %T A134560 0,0,15,1,0,5,0,0,0,0,0,17,1,3,0,0,9,0,0,0,0,19,1,0,0,0,0,0,0,0,0,0, %U A134560 21,1,3,5,7,0,11,0,0,0,0,0,23 %N A134560 Triangle A051731 * A127775 (as infinite lower triangular matrices). %C A134560 Obtained also by replacing the 1's in column k of A051731 with (2k-1). %e A134560 First few rows of the triangle: %e A134560 1; %e A134560 1, 3; %e A134560 1, 0, 5; %e A134560 1, 3, 0, 7; %e A134560 1, 0, 0, 0, 9; %e A134560 1, 3, 5, 0, 0, 11; %e A134560 1, 0, 0, 0, 0, 0, 13; %e A134560 1, 3, 0, 7, 0, 0, 0, 15; %e A134560 ... %Y A134560 Cf. A129235 (row sums), A051731, A127775. %K A134560 nonn,tabl %O A134560 1,3 %A A134560 _Gary W. Adamson_, Oct 31 2007