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 A131873 #14 Jun 02 2025 00:32:03 %S A131873 1,8,4,15,8,7,22,12,11,10,29,16,15,14,13,36,20,19,18,17,16,43,24,23, %T A131873 22,21,20,19,50,28,27,26,25,24,23,22,57,32,31,30,29,28,27,26,25,64,36, %U A131873 35,34,33,32,31,30,29,28,71,40,39,38,37,36,35,34,33,32,31,78,44,43,42,41,40,39,38,37,36,35,34,85,48,47,46,45,44,43,42,41,40,39,38,37,92,52,51,50,49,48,47,46,45,44,43,42,41,40 %N A131873 Right-to-left partial row sums of triangle A131844. %C A131873 Left column = A016993, 7n + 1: (1, 8, 15, 22, 29, ...). %C A131873 Right border = 3n + 1: (1, 4, 7, 10, 13, ...). %C A131873 Row sums = A131874: (1, 12, 30, 55, ...). %e A131873 First few rows of the triangle: %e A131873 1; %e A131873 8, 4; %e A131873 15, 8, 7; %e A131873 22, 12, 11, 10; %e A131873 29, 16, 15, 14, 13; %e A131873 36, 20, 19, 18, 17, 16; %e A131873 43, 24, 23, 22, 21, 20, 19; %e A131873 ... %e A131873 Row 4 of A131844 is 13, 1, 1, 1, 13, so row 4 of this sequence is 29, 16, 15, 14, 13. %Y A131873 Cf. A131844, A131874, A016993, A131875. %K A131873 nonn,tabl %O A131873 0,2 %A A131873 _Gary W. Adamson_, Jul 22 2007 %E A131873 Definition corrected and more terms added by _Russ Cox_, Apr 18 2024