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 A080110 #13 Sep 20 2022 07:54:49 %S A080110 0,1,1,1,1,1,0,0,1,0,1,1,0,0,1,0,1,0,0,1,0,1,1,0,0,0,1,0,0,0,0,1,0,0, %T A080110 0,1,0,0,1,0,0,0,1,0,0,1,0,0,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,0, %U A080110 0,0,0,1,0,0,0,1,0,0,0,0,1,0,1,0,1,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,1,0,0 %N A080110 Characteristic function of A080112. %H A080110 <a href="/index/Ch#char_fns">Index entries for characteristic functions</a> %p A080110 A080110 := n -> A080116(A080117(n)); %o A080110 (Sage) %o A080110 def A080110(n) : return A080116(A080117(n)) # _Peter Luschny_, Aug 09 2012 %K A080110 nonn %O A080110 1,1 %A A080110 _Antti Karttunen_, Feb 11 2003