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 A153868 #5 Apr 26 2021 14:53:12 %S A153868 1,2,1,3,3,3,4,6,12,9,5,10,30,45,31,6,15,60,135,186,121,7,21,105,315, %T A153868 651,847,523,8,28,168,630,1736,3388,4184,2469 %N A153868 Triangle read by rows, A135278 * (A040027 * 0^(n-k)). %C A153868 Row sums = A040027 starting (1, 3, 9, 31, 121, 523,...). %C A153868 Sum of n-th row terms = rightmost term of next row. %F A153868 Triangle read by rows, A135278 * (A040027 * 0^(n-k)). %F A153868 Binomial transform of an infinite lower triangular matrix with A040027. %F A153868 (starting 1, 1, 3, 9, 31, 121,...) as the main and subdiagonals. %e A153868 First few rows of the triangle %e A153868 1; %e A153868 2, 1; %e A153868 3, 3, 3; %e A153868 4, 6, 12, 9; %e A153868 5, 10, 30, 45, 31; %e A153868 6, 15, 60, 135, 186, 121; %e A153868 7, 21, 105, 315, 651, 846, 523; %e A153868 8, 28, 168, 630, 1736, 3388, 4184, 2469; %e A153868 ... %Y A153868 Cf. A040027, A135278. %K A153868 nonn,tabl %O A153868 0,2 %A A153868 _Gary W. Adamson_, Jan 03 2009