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 A131784 #12 Aug 09 2023 03:03:43 %S A131784 1,5,2,11,7,3,19,14,9,4,29,23,17,11,5,41,34,27,20,13,6,55,47,39,31,23, %T A131784 15,7,71,62,53,44,35,26,17,8,89,79,69,59,49,39,29,19,9,109,98,87,76, %U A131784 65,54,43,32,21,10,131,119,107,95,83,71,59,47,35,23,11,155,142,129,116,103,90,77,64,51,38,25,12 %N A131784 Triangle read by rows: (A004736 + A002260 - I) * A000012. %F A131784 Equals (A004736 + A002260 - I) * A000012, I = Identity matrix. %e A131784 First few rows of the triangle: %e A131784 1; %e A131784 5, 2; %e A131784 11, 7, 3; %e A131784 19, 14, 9, 4; %e A131784 29, 23, 17, 11, 5; %e A131784 41, 34, 27, 20, 13, 6; %e A131784 55, 47, 39, 31, 23, 15, 7; %e A131784 ... %Y A131784 Cf. A004736, A002260, A127736 (row sums), A028387 (left column). %K A131784 nonn,tabl %O A131784 1,2 %A A131784 _Gary W. Adamson_, Jul 16 2007 %E A131784 a(35) corrected and more terms from _Georg Fischer_, Aug 09 2023