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 A048119 #4 Mar 30 2012 18:56:54 %S A048119 1,3,9,30,102,360,1290,4704,17334,64512,241836,912384,3459876, %T A048119 13178988,50389236,193295652,743610528,2867892588,11085281328, %U A048119 42933166380,166575534264,647329281456,2519234973996,9817121868084 %N A048119 a(n)=(1/2)*T(2n+1,n+1), where T is given by A048113. %K A048119 nonn %O A048119 2,2 %A A048119 _Clark Kimberling_