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 A091678 #5 Jul 11 2015 00:51:57 %S A091678 0,2,4,5,6,10,15,17,20,25,30,33,34,41,42,50,51,58,59,65,67,68,75,76, %T A091678 84,85,92,93,101,102,105,109,110,118,125,126,130,145,150,165,170,185, %U A091678 190,195,210,215,230,235,250,255,257,260,275,280,289,295,300,315,320,321 %N A091678 In base 4, numbers n of the form k + reverse(k) for at least one k. %C A091678 Base-4 analog of A067030. Complement of A091679. %e A091678 25 is a term since 25 (decimal) = 121 = 110 + 011 = 20 (decimal) + 5 (decimal). %Y A091678 Cf. A035524, A091679, A067030. %K A091678 base,easy,nonn %O A091678 0,2 %A A091678 _Klaus Brockhaus_, Jan 28 2004