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 A232806 #20 Jun 08 2020 02:46:04 %S A232806 1,3,7,27,367,67347,2267809207,2571479299676984427, %T A232806 3306252894333617140505030630200259167 %N A232806 a(n) = a(n-1)^2/2 + 5/2, a(0) = 1. %C A232806 First differences are 2*A063573. %F A232806 a(n) = 2*A002065(n) + 1. %F A232806 a(n) = 2*A166105(n) - 1. - _Robert FERREOL_, May 31 2020 %F A232806 a(n) = A002065(n) + A166105(n). - _Alois P. Heinz_, Jun 07 2020 %Y A232806 Cf. A063573, A002065, A166105. %K A232806 nonn %O A232806 0,2 %A A232806 _Richard R. Forberg_, Nov 30 2013