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 A258977 #24 Sep 08 2022 08:46:13
%S A258977 2,17,37,197,577,577,401,1297,577,1601,3137,2917,3137,8101,7057,15377,
%T A258977 2917,14401,14401,8101,7057,15877,5477,15377,15877,7057,50177,14401,
%U A258977 32401,8101,14401,24337,44101,78401,12101,57601,44101,32401,50177,24337,30977
%N A258977 Primes in A258974.
%C A258977 These primes are neither sorted nor uniqued. They are listed in the order found in A258974.
%H A258977 Robert Price, <a href="/A258977/b258977.txt">Table of n, a(n) for n = 1..1786</a>
%H A258977 OEIS Wiki, <a href="https://oeis.org/wiki/Cyclotomic Polynomials at x=n, n! and sigma(n)">Cyclotomic Polynomials at x=n, n! and sigma(n)</a>
%F A258977 a(n) = A258974(A258976(n)).
%p A258977 with(numtheory): A258977:=n->`if`(isprime(1+sigma(n)^2), 1+sigma(n)^2, NULL): seq(A258977(n), n=1..300); # _Wesley Ivan Hurt_, Jul 09 2015
%t A258977 Select[Table[1 + DivisorSigma[1, n]^2, {n, 10000}], PrimeQ]
%t A258977 Select[Table[Cyclotomic[4, DivisorSigma[1, n]], {n, 10000}], PrimeQ]
%o A258977 (Magma) [m: n in [1..200] | IsPrime(m) where m is 1 + DivisorSigma(1, n)^2]; // _Vincenzo Librandi_, Jun 16 2015
%o A258977 (PARI) for(n=1,100,p=1+sigma(n)^2;if(isprime(p),print1(p,", "))) \\ _Derek Orr_, Jun 18 2015
%Y A258977 Cf. A000203, A258974, A258976.
%K A258977 nonn
%O A258977 1,1
%A A258977 _Robert Price_, Jun 15 2015