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 A124747 #2 Mar 30 2012 18:59:18 %S A124747 1,0,1,0,0,1,0,0,1,1,0,0,1,1,1,0,0,2,2,2,1,0,0,3,3,3,2,1,0,0,7,7,7,5, %T A124747 3,1,0,0,12,12,12,9,6,3,1,0,0,30,30,30,23,16,9,4,1,0,0,55,55,55,43,31, %U A124747 19,10,4,1 %N A124747 Inverse of number triangle A124744. %C A124747 Third column and row sums give A047749. %e A124747 Triangle begins %e A124747 1, %e A124747 0, 1, %e A124747 0, 0, 1, %e A124747 0, 0, 1, 1, %e A124747 0, 0, 1, 1, 1, %e A124747 0, 0, 2, 2, 2, 1, %e A124747 0, 0, 3, 3, 3, 2, 1, %e A124747 0, 0, 7, 7, 7, 5, 3, 1, %e A124747 0, 0, 12, 12, 12, 9, 6, 3, 1 %K A124747 nonn,tabl %O A124747 0,18 %A A124747 _Paul Barry_, Nov 06 2006