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 A055965 #3 Mar 30 2012 18:51:27 %S A055965 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,15,0,-15,-30,-45,-60,-75,-90,-105, %T A055965 -120,-135,-150,-165,-180,-195,-210,30,15,0,-15,-30,-45,-60,-75,-90, %U A055965 -105,-120,-135,-150,-165,-180,-195,45,30,15,0,-15,-30,-45,-60,-75,-90,-105,-120,-135,-150,-165,-180,60,45,30,15,0 %N A055965 n - reversal of hexadecimal (base 16) digits of n (written in base 10). %C A055965 a(n) is a multiple of 15 %F A055965 a(n) =n-A056962(n) %Y A055965 Cf. A056965. %K A055965 base,sign %O A055965 0,17 %A A055965 _Henry Bottomley_, Jul 18 2000