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 A134870 #6 Mar 27 2022 18:31:30 %S A134870 1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,2,2,1,1,1,1,1,1,1,1,1,1,1,2,1,2,1,1, %T A134870 1,1,1,1,2,1,1,1,1,1,1,1,2,1,1,2,1,1,1,1,1 %N A134870 A051731 + A000012 - A103451. %C A134870 Row sums = A134871: (1, 2, 3, 5, 5, 8, 7, 10, 10, 12, 11, ...). %F A134870 A051731 + A000012 - A103451 as infinite lower triangular matrices. %e A134870 First few rows of the triangle: %e A134870 1; %e A134870 1, 1; %e A134870 1, 1, 1; %e A134870 1, 2, 1, 1; %e A134870 1, 1, 1, 1, 1; %e A134870 1, 2, 2, 1, 1, 1; %e A134870 1, 1, 1, 1, 1, 1, 1; %e A134870 1, 2, 1, 2, 1, 1, 1, 1; %e A134870 ... %Y A134870 Cf. A051731, A134871, A103451, A000012. %K A134870 nonn,tabl %O A134870 1,8 %A A134870 _Gary W. Adamson_, Nov 14 2007