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 A025568 #5 Mar 30 2012 18:56:04 %S A025568 1,5,19,65,211,665,2058,6294,19095,57607,173096,518596,1550367, %T A025568 4627455,13795176,41088456,122297643,363828663,1081966875,3216725841, %U A025568 9561635853,28418162003,84455354206,250982289650,745860104145,2216567725281 %N A025568 a(n) = T(n,n+2) where T is the array defined in A025564. %Y A025568 First differences are pairwise sums of A025181. %Y A025568 Pairwise sums of A014532. %K A025568 nonn %O A025568 1,2 %A A025568 _Clark Kimberling_