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 A180264 #2 Mar 30 2012 17:25:39 %S A180264 1,1,1,2,2,1,1,1,4,5,1,1,2,10,11,1,1,2,5,22,25,1,1,2,5,11,50,56,1,1,2, %T A180264 5,11,50,56,1,1,2,5,11,25,112,126,1,1,2,5,11,25,56,252,283,1,1,2,5,11, %U A180264 25,56,126,566,636,1,1,2,5,11,25,56,126,283,1272,1429 %N A180264 Triangle, row sums = A006054; derived from an infinite lower triangular matrix with (1,1,1,...) as the leftmost column and (1,2,1,1,1,...) as other columns. %C A180264 Row sums = A006054 starting (1, 2, 5, 11, 25, 56, 126,...). %C A180264 Sum of n-th row terms = rightmost term of next row. %F A180264 Let M = an infinite lower triangular matrix with 1's in the leftmost column, %F A180264 and (1,2,1,1,1,...) as other columns. Let Q = a diagonalized variant of %F A180264 A006054 (1, 1, 2, 5, 11, 25, 56,...) as the right border and the rest zeros. %F A180264 Triangle A180264 = M*Q. %e A180264 First few rows of the triangle = %e A180264 . %e A180264 1; %e A180264 1, 1; %e A180264 1, 2, 2; %e A180264 1, 1, 4, 5; %e A180264 1, 1, 2, 10, 11; %e A180264 1, 1, 2, 5, 22, 25; %e A180264 1, 1, 2, 5, 11, 50, 56; %e A180264 1, 1, 2, 5, 11, 25, 112, 126; %e A180264 1, 1, 2, 5, 11, 25, 56, 252, 283; %e A180264 1, 1, 2, 5, 11, 25, 56, 126, 566, 636; %e A180264 1, 1, 2, 5, 11, 25, 56, 126, 283, 1272, 1429; %e A180264 1, 1, 2, 5, 11, 25, 56, 126, 283, 636, 2858, 3211; %e A180264 ... %e A180264 Example: Row 4 = (1, 1, 4, 5) = termwise products of (1, 1, 2, 1) and (1, 1, 2, 5). %Y A180264 Cf. A006054 %K A180264 nonn,tabf %O A180264 1,4 %A A180264 _Gary W. Adamson_, Aug 21 2010