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 A272171 #17 Apr 24 2016 22:38:02 %S A272171 1,2,1,2,2,1,3,2,2,1,2,3,2,2,1,4,2,3,2,2,1,2,4,2,3,2,2,1,4,2,4,2,3,2, %T A272171 2,1,3,4,2,4,2,3,2,2,1,4,3,4,2,4,2,3,2,2,1,2,4,3,4,2,4,2,3,2,2,1,6,2, %U A272171 4,3,4,2,4,2,3,2,2,1,2,6,2,4,3,4,2,4,2,3,2,2,1,4,2,6,2,4,3,4,2,4,2,3,2,2,1 %N A272171 Triangle read by rows: T(n,k) in which row n lists the first n terms of A000005 in reverse order. %F A272171 a(n) = A000005(A004736(n)). %F A272171 T(n,k) = A000005(n-k+1). %e A272171 Triangle begins: %e A272171 1; %e A272171 2, 1; %e A272171 2, 2, 1; %e A272171 3, 2, 2, 1; %e A272171 2, 3, 2, 2, 1; %e A272171 4, 2, 3, 2, 2, 1; %e A272171 2, 4, 2, 3, 2, 2, 1; %e A272171 4, 2, 4, 2, 3, 2, 2, 1; %e A272171 3, 4, 2, 4, 2, 3, 2, 2, 1; %e A272171 4, 3, 4, 2, 4, 2, 3, 2, 2, 1; %e A272171 2, 4, 3, 4, 2, 4, 2, 3, 2, 2, 1; %e A272171 6, 2, 4, 3, 4, 2, 4, 2, 3, 2, 2, 1; %e A272171 ... %Y A272171 Column k gives A000005 starting in row k. %Y A272171 Row sums give A006218, n >= 1. %Y A272171 Cf. A004736, A104887, A272172. %K A272171 nonn,tabl %O A272171 1,2 %A A272171 _Omar E. Pol_, Apr 21 2016