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 A366079 #29 Sep 29 2023 03:36:30 %S A366079 1,81,121,361,1352569,2140369,6416089,9186961,30261001,108056025, %T A366079 820765201,2331248089,170938421809,8189950752481,8870860603201, %U A366079 33527956250889,136943052939289,149526943190641,4953581020385761,509672946670475329,578899033007097609,2043000477545048329 %N A366079 Perfect squares in A005728. %e A366079 a(3) = 361 because A005728(34) = 361 and 361 is 19 squared. %o A366079 (PARI) f(n)=1+sum(k=1, n, eulerphi(k)); \\ A005728 %o A366079 select(x->issquare(x), apply(f, [0..10^5])) \\ _Michel Marcus_, Sep 28 2023 %Y A366079 Cf. A000290, A005728. %K A366079 nonn %O A366079 1,2 %A A366079 _Stuart E Anderson_, Sep 28 2023 %E A366079 a(11)-a(12) from _Michel Marcus_, Sep 28 2023 %E A366079 a(13)-a(22) from _Hugo Pfoertner_, Sep 28 2023