%I #4 Oct 01 2022 19:35:19

%S 5,19,263,1667

%N Primes p such that either p^(q-1) == 1 (mod q^2) or q^(p-1) == 1 (mod p^2), where q = A151800(A151800(p)).

%o (PARI) is(n) = my(b=precprime(precprime(n-1)-1)); Mod(b, n^2)^(n-1)==1 || Mod(n, b^2)^(b-1)==1

%o forprime(p=5, , if(is(p), print1(p, ", ")))

%Y Cf. A151800, A357362, A357364, A357365.

%K nonn,hard,more

%O 1,1

%A _Felix Fröhlich_, Sep 25 2022