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 A130461 #11 Feb 21 2022 00:15:04 %S A130461 1,1,1,1,1,1,1,1,2,1,1,1,2,3,1,1,1,2,6,4,1,1,1,2,6,12,5,1,1,1,2,6,24, %T A130461 20,6,1,1,1,2,6,24,60,30,7,1,1,1,2,6,24,120,120,42,8,1,1,1,2,6,24,120, %U A130461 360,210,56,9,1,1,1,2,6,24,120,720,840,336,72,10,1,1,1,2,6,24,120,720,2520 %N A130461 Triangle, antidiagonals of an array generated from A130460. %C A130461 Rows tend to the factorials: (1, 1, 2, 6, 24, ...). Row sums = A130476: (1, 2, 3, 5, 8, 15, 28, 61, 132, ...). %F A130461 Let A130460 = M, an infinite lower triangular matrix and V = [1, 1, 1, ...], the first row of an array. Perform M * V = second row, ...; (n+1)-th row = M * n-th row. The triangle = antidiagonals of the array. %e A130461 The array = %e A130461 1, 1, 1, 1, 1, 1, ... %e A130461 1, 1, 2, 3, 4, 5, ... %e A130461 1, 1, 2, 6, 12, 20, ... %e A130461 1, 1, 2, 6, 24, 60, ... %e A130461 1, 1, 2, 6, 24, 120, ... %e A130461 1, 1, 2, 6, 24, 120, ... %e A130461 ... %e A130461 First few rows of the triangle: %e A130461 1; %e A130461 1, 1; %e A130461 1, 1, 1; %e A130461 1, 1, 2, 1; %e A130461 1, 1, 2, 3, 1; %e A130461 1, 1, 2, 6, 4, 1; %e A130461 1, 1, 2, 6, 12, 5, 1; %e A130461 1, 1, 2, 6, 24, 20, 6, 1; %e A130461 1, 1, 2, 6, 24, 60, 30, 7, 1; %e A130461 ... %Y A130461 Cf. A130460, A130476, A130477, A130478. %K A130461 nonn,tabl %O A130461 0,9 %A A130461 _Gary W. Adamson_, May 28 2007 %E A130461 a(23) and a(38) corrected by _Gionata Neri_, Jun 22 2016