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 A049089 #13 Jul 19 2021 01:43:30 %S A049089 4,6,6,8,10,8,10,16,14,10,12,24,24,18,12,14,34,40,32,22,14,16,46,64, %T A049089 56,40,26,16,18,60,98,96,72,48,30,18,20,76,144,160,128,88,56,34,20,22, %U A049089 94,204,258,224,160,104,64,38,22,24,114,280,402,384,288,192,120,72,42,24,26,136,374,606,642 %N A049089 Array read by antidiagonals: T(1,j)=2j+2 i>=1, T(i,1)=2i+2 i>=1, T(i,j)=T(i-1,j-1)+T(i-1,j). %e A049089 Table begins: %e A049089 4, 6, 8, 10, 12, ... %e A049089 6, 10, 14, 18, 22, ... %e A049089 8, 16, 24, 32, 40, ... %e A049089 10, 24, 40, 56, 72, ... %e A049089 12, 34, 64, 96, 128, ... %e A049089 ... %Y A049089 Cf. A079859. %K A049089 nonn,tabl,easy %O A049089 1,1 %A A049089 _Benoit Cloitre_, Jun 17 2003 %E A049089 Offset corrected by _Sean A. Irvine_, Jul 18 2021