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 A112740 #2 Mar 30 2012 18:59:12
%S A112740 1,2,4,7,13,26,58,147,423,1366,4880,19039,80281,362914,1747598,
%T A112740 8918299,48024291,271891710,1613325844,10005690695,64702147429,
%U A112740 435311589418,3041246276098,22024930755299,165082467634303,1278742554953574
%N A112740 Row sums of number triangle A112739.
%F A112740 a(n)=sum{k=0..n, sum{j=0..k, (2-0^j)*(n-1)^(k-j)}}.
%K A112740 easy,nonn
%O A112740 0,2
%A A112740 _Paul Barry_, Sep 16 2005