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 A144155 #9 Jun 02 2025 00:34:13 %S A144155 1,1,1,2,1,2,5,2,2,5,15,5,4,5,15,52,15,10,10,15,52,203,52,30,25,30,52, %T A144155 203,877,203,104,75,75,104,203,877,4140,877,406,260,225,260,406,877, %U A144155 4140,21147,4140,1754,1015,780,780,1015,1754,4140,21147 %N A144155 Bell convolution triangle, T(n,k) = A000110(n-k)*A000110(k). %C A144155 Row sums = A014322: (1, 2, 5, 14, 44, 154,...) the Bell numbers convolved with themselves. %F A144155 Triangle read by rows, T(n,k) = A000110(n-k)*A000110(k) %e A144155 First few rows of the triangle = %e A144155 1; %e A144155 1, 1; %e A144155 2, 1, 2; %e A144155 5, 2, 2, 5; %e A144155 15, 5, 4, 5, 15; %e A144155 52, 15, 10, 10, 15, 52; %e A144155 203, 52, 30, 25, 30, 52, 203; %e A144155 ... %e A144155 Row 3 = (5, 2, 2, 5) = termwise products of (1, 1, 2, 5) and (5, 2, 1, 1) = (5*1, 1*2, 2*1, 5*1). %Y A144155 A000110, Cf. A014322 %K A144155 nonn,tabl %O A144155 0,4 %A A144155 _Gary W. Adamson_, Sep 12 2008 %E A144155 More terms from _Philippe Deléham_, Jan 29 2012