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%I #9 Jul 17 2015 15:04:10
%S 157,1069,61837,190573,840109,1950349,2485453,20616397,38844349,
%T 57648589,133091053,144685357,188582029,222029869,276773389,346282477,
%U 399067213,472656589,827175949,929558797,1137622957,1352220109,1369037389
%N Primes p of form x^2 - phi(x) such that (p-1)/tau(p-1) is also prime.
%C Intersection of A252021 and A258435.
%t lst = Table[n^2 - EulerPhi[n], {n, 100000}]; Select[lst, PrimeQ[#] && PrimeQ[ ( # - 1)/DivisorSigma[0, # - 1] ] &]
%o (PARI) lista(nn) = {for (n=1, nn, if (isprime(p=n^2-eulerphi(n)) && (pp=p-1) && (type(r=pp/numdiv(pp))=="t_INT") && isprime(r), print1(p, ", ")););} \\ _Michel Marcus_, Jul 08 2015
%Y Cf. A252021, A258435.
%K nonn,easy
%O 1,1
%A _Carlos Eduardo Olivieri_, May 30 2015