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 A154109 #5 Dec 26 2023 13:06:35 %S A154109 1,2,0,3,0,2,4,0,4,7,5,0,6,14,27,6,0,8,21,54,114,7,0,10,28,81,228,523, %T A154109 8,0,12,35,108,342,1046,2589,9,0,14,42,135,456,1569,5178,13744,10,0, %U A154109 16,49,162,570,2092,7767,27488,77821 %N A154109 Convolution triangle by rows, A004736 * (A154108 * 0^(n-k)); row sums = Bell numbers. %C A154109 Row sums = Bell numbers, A000110 starting (1, 2, 5, 15, 52, 203, 877,...). %F A154109 A004736 * (A154108 * 0^(n-k)); where A004736 = an infinite lower triangular %F A154109 matrix with (1,2,3,...) in every column and (A154108 * 0^(n-k)) = a matrix %F A154109 with A154108 (1, 0, 2, 7, 27, 114, 523, 2589...) as the main diagonal %F A154109 and the rest zeros. %e A154109 First few rows of the triangle = %e A154109 1; %e A154109 2, 0; %e A154109 3, 0, 2; %e A154109 4, 0, 4, 7; %e A154109 5, 0, 6, 14, 27; %e A154109 6, 0, 8, 21, 54, 114; %e A154109 7, 0, 10, 28, 81, 228, 523; %e A154109 8, 0, 12, 35, 108, 342, 1046, 2589; %e A154109 9, 0, 14, 42, 135, 456, 1569, 5178, 13744; %e A154109 10, 0, 16, 49, 162, 570, 2092, 7767, 27488, 77821; %e A154109 ... %e A154109 Row 5 = (5, 0, 6, 14, 27), sum = A000110(5) = 52 = termwise products of %e A154109 (5, 4, 3, 2, 1) and (1, 0, 2, 7, 27). %Y A154109 Cf. A154108, A000110. %K A154109 nonn,tabl %O A154109 1,2 %A A154109 _Gary W. Adamson_, Jan 04 2009