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 A261918 #9 Sep 14 2015 07:41:42 %S A261918 11,17,23,51,131,141,146,147,149,151,153,154,163,164,169,173,175,177, %T A261918 179,181,184,185,194,195,199,200,201,203,205,206,211,215,221,225,226, %U A261918 229,231,236,237,241,251,259,261,262,263,266,267,271,281,287,289,291,296,297 %N A261918 Numbers which in base 5 are neither palindromes nor the sum of two palindromes. %C A261918 The terms less than 20000, and conjecturally all terms, are the sum of three base 5 palindromes. %H A261918 N. J. A. Sloane, <a href="/A261918/b261918.txt">Table of n, a(n) for n = 1..6235</a> %Y A261918 Cf. A029952, A261917; A035137 (base 10 analog). %K A261918 nonn,base %O A261918 1,1 %A A261918 _N. J. A. Sloane_, Sep 13 2015