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 A087310 #8 Jun 21 2021 06:07:13 %S A087310 1,2,6,6,30,4,72,72,210,132,132,114,594,48,354,1860,3942,2574,2574, %T A087310 2574,20910,20910,9600,9600 %N A087310 Common differences of arithmetic progressions in A086786. %F A087310 a(n) = A086786(n, 2) - A086786(n, 1) = (A087309(n) - A087308(n))/(n - 1). %Y A087310 Cf. A086786, A087308, A087309. %K A087310 nonn,more %O A087310 2,2 %A A087310 _Amarnath Murthy_, Sep 02 2003 %E A087310 Edited and extended by _David Wasserman_, Jan 08 2006