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 A124752 #2 Mar 30 2012 18:59:18 %S A124752 1,0,1,0,0,1,0,0,0,1,0,0,0,1,1,0,0,0,1,1,1,0,0,0,1,1,1,1,0,0,0,2,2,2, %T A124752 2,1,0,0,0,3,3,3,3,2,1,0,0,0,4,4,4,4,3,2,1,0,0,0,9,9,9,9,7,5,3,1 %N A124752 Inverse of number triangle A124749. %C A124752 Row sums (and fourth column) are A124753. %e A124752 Triangle begins %e A124752 1, %e A124752 0, 1, %e A124752 0, 0, 1, %e A124752 0, 0, 0, 1, %e A124752 0, 0, 0, 1, 1, %e A124752 0, 0, 0, 1, 1, 1, %e A124752 0, 0, 0, 1, 1, 1, 1, %e A124752 0, 0, 0, 2, 2, 2, 2, 1, %e A124752 0, 0, 0, 3, 3, 3, 3, 2, 1, %e A124752 0, 0, 0, 4, 4, 4, 4, 3, 2, 1, %e A124752 0, 0, 0, 9, 9, 9, 9, 7, 5, 3, 1 %Y A124752 Cf. A124747. %K A124752 nonn,tabl %O A124752 0,32 %A A124752 _Paul Barry_, Nov 06 2006