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 A261920 #7 Sep 15 2015 15:45:16 %S A261920 10,109,110,113,114,115,116,117,118,119,120,124,125,126,127,128,129, %T A261920 130,135,136,137,138,139,140,146,147,148,149,150,157,158,159,160,168, %U A261920 169,170,179,180,190,211,221,231,241,251,261,271,281,291,302,312,322,332,342 %N A261920 In A261907 but not the sum of two palindromes whose lengths differ by 1. %C A261920 Nonpalindromes which are the sum of two palindromes but are not the sum of two palindromes whose lengths differ by 1. %e A261920 10 = 5+5 is a member, as is 109=101+8. %Y A261920 Cf. A002113, A261907, A261921. %K A261920 nonn,base %O A261920 1,1 %A A261920 _David Applegate_ and _N. J. A. Sloane_, Sep 15 2015