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 A122004 #12 Feb 20 2021 00:36:24
%S A122004 2,3,5,23,29
%N A122004 Primes p that divide A123373(p-1).
%e A122004 A123373 begins {4, 48, 3598, 924780, 287358579128, ...}.
%e A122004 a(1) = 2 because 2 divides A123373(1) = 4.
%e A122004 a(2) = 3 because 3 divides A123373(2) = 48.
%e A122004 a(3) = 5 because 5 divides A123373(4) = 924780.
%o A122004 (PARI) is(p) = isprime(p) && sum(j=1, p-1, sum(k=1, p-1, Mod(prime(k), p)^prime(j))) == 0; \\ _Jinyuan Wang_, Jan 16 2021
%o A122004 (Python)
%o A122004 from sympy import nextprime, prime
%o A122004 p, A122004_list = 2, []
%o A122004 while p < 10**6:
%o A122004 if 0 == sum(pow(prime(i),prime(j),p) for i in range(1,p) for j in range(1,p)) % p:
%o A122004 A122004_list.append(p)
%o A122004 p = nextprime(p) # _Chai Wah Wu_, Feb 19 2021
%Y A122004 Cf. A086787, A123373.
%K A122004 nonn,more,hard
%O A122004 1,1
%A A122004 _Alexander Adamchuk_, Oct 14 2006