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 A113798 #11 Aug 30 2019 06:10:55 %S A113798 117,119817,13101687,119819817,13101801687,119819819817, %T A113798 11983101689817,13101801801687,119819819819817 %N A113798 Numbers k such that k^2 plus the reverse of k is a square. %C A113798 a(10) > 1.36*10^14. The sequence contains two infinite sets, 117*1000^k + 2817*(1000^k - 1)/999 and 13101687*1000^k + 114687*(1000^k - 1)/999, for k >= 0. Terms of both sets satisfy the equation rev(x) = 6*x + 9, and thus x^2 + rev(x) = (x+3)^2. - _Giovanni Resta_, Aug 26 2019 %e A113798 117^2 + 711 = 120^2, thus 117 is a term. %Y A113798 Cf. A004086, A068536, A202386. %K A113798 nonn,base,more %O A113798 1,1 %A A113798 _Giovanni Resta_, Jan 21 2006 %E A113798 a(5)-a(6) from _Giovanni Resta_, May 10 2017 %E A113798 a(7)-a(9) from _Giovanni Resta_, Aug 26 2019