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 A116012 #8 Jul 15 2021 06:35:10 %S A116012 19,1873,147497,792736,4551733,4967176,7333813,8539521,8674128, %T A116012 12388853,12948373,18331664,24834369,36294936,50952310,116340016, %U A116012 170434387,196966352,222505713,236504256,286766145,390771936,426323088,532998481,778930925,805653001 %N A116012 Numbers k such that k + sigma(k) + sigma(sigma(k)) is a fourth power. %e A116012 792736 + sigma(792736) + sigma(sigma(792736)) = 56^4. %o A116012 (PARI) for(n=1, 10^9, s=sigma(n); if(ispower(n+s+sigma(s), 4), print(n))) /* _Donovan Johnson_, Feb 17 2013 */ %Y A116012 Cf. A116013, A116014, A116015. %K A116012 nonn %O A116012 1,1 %A A116012 _Giovanni Resta_, Feb 13 2006 %E A116012 a(5)-a(26) from _Donovan Johnson_, Feb 17 2013