%I

%S 1,171,210

%N Numbers n such that A075986(n) is prime.

%t f=1; Do[ p=Prime[n]; f=f + 1/p^2; g=Numerator[ f ]; If[ PrimeQ[ g ], Print[ {n, g} ] ], {n, 1, 210} ]

%Y Cf. A075986 = Numerator of 1+1/p(1)^2+ ... + 1/p(n)^2, where p(k) = k-th prime. Cf. A024528, A125707. Cf. A136366, A136367, A136368, A136369, A136370, A136371.

%K bref,hard,more,nonn

%O 1,2

%A _Alexander Adamchuk_, Dec 27 2007