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 A120772 #3 Oct 19 2017 03:15:03 %S A120772 21,42,33,84,66,57,168,132,114,69,336,264,228,138,77,672,528,456,276, %T A120772 154,93,1344,1056,912,552,308,186,105,2688,2112,1824,1104,616,372,210, %U A120772 129,5376,4224,3648,2208,1232,744,420,258,133,10752,8448,7296,4416 %N A120772 Triangular array, permutation of A119973. a(r,r) = A084109(r); a(r+1,c) = 2*a(r,c). %e A120772 21 %e A120772 42 33 %e A120772 84 66 57 %e A120772 168 132 114 69 %e A120772 336 264 228 138 77 %Y A120772 Cf. A001481, A084109, A119973. %K A120772 easy,nonn,tabl %O A120772 1,1 %A A120772 _Alford Arnold_, Jul 04 2006 %E A120772 Edited by _Don Reble_, Jul 24 2006