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 A131432 #10 Jun 05 2023 05:22:46 %S A131432 1,4,7,7,10,13,10,13,16,19,13,16,19,22,25,16,19,22,25,28,31,19,22,25, %T A131432 28,31,34,37,22,25,28,31,34,37,40,43,25,28,31,34,37,40,43,46,49,28,31, %U A131432 34,37,40,43,46,49,52,55,31,34,37,40,43,46,49,52,55,58,61,34,37,40,43,46,49,52,55,58,61,64,67 %N A131432 Triangle read by rows: (A000012 * A131431) + (A131431 * A000012) - A000012 as infinite lower triangular matrices. %C A131432 Left border = A016777, (1, 4, 7, 10, 13, ...). %C A131432 Right border = A016921: (1, 7, 13, 19, 25, ...). %C A131432 Row sums = A051682, 11-gonal numbers: (1, 11, 30, 58, 95, ...). %e A131432 First few rows of the triangle: %e A131432 1; %e A131432 4, 7; %e A131432 7, 10, 13; %e A131432 10, 13, 16, 19; %e A131432 13, 16, 19, 22, 25; %e A131432 16, 19, 22, 25, 28, 31; %e A131432 19, 22, 25, 28, 31, 34, 37; %e A131432 ... %Y A131432 Cf. A016777, A051682, A131431, A016921. %K A131432 nonn,tabl %O A131432 0,2 %A A131432 _Gary W. Adamson_, Jul 10 2007 %E A131432 a(28) ff. corrected and more terms from _Georg Fischer_, Jun 05 2023