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 A087239 #6 Sep 01 2018 17:44:05 %S A087239 25,69,234,678,2051,5349,15118,41014,110657,305655,823646,2219386, %T A087239 6034071,16316797,44240660,119845770,324311229,879921169,2385656018, %U A087239 6467086046,17541630385,47581555131,129104931215,350330768077,950772203169,2580621278375,7005302328953 %N A087239 First differences of A038625. %H A087239 Giovanni Resta, <a href="/A087239/b087239.txt">Table of n, a(n) for n = 2..49</a> %F A087239 a(n)=A038625(n+1)-A038625(n) %Y A087239 Cf. A038623-A038627, A057809, A087235-A087241. %K A087239 nonn %O A087239 2,1 %A A087239 _Labos Elemer_, Sep 04 2003 %E A087239 More terms from _Giovanni Resta_, Sep 01 2018