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 A115892 #11 Jul 15 2021 21:23:26 %S A115892 1,2,3,69,219,221,224,254,1772,2181,15463,50807,63551,94236,161257, %T A115892 602962,2105689,8371756,2115856505,2539027806,5472276593,6819131191, %U A115892 15442198064,16190055003,46870943027 %N A115892 Numbers k such that sigma(k)*phi(k) is a palindrome. %C A115892 a(26) > 5*10^10. 205447718981 is also a term. - _Donovan Johnson_, Sep 30 2011 %e A115892 sigma(15463)*phi(15463) = 18056*12972 = 234222432. %Y A115892 Cf. A084122, A115890, A115891. %K A115892 nonn,base %O A115892 1,2 %A A115892 _Giovanni Resta_, Feb 06 2006 %E A115892 a(19)-a(25) from _Donovan Johnson_, Sep 30 2011