|
%I #20 Jul 28 2021 18:44:27
%S 2,3,13,29,31,37,61,67,71,103,109,139,149,167,191,223,229,241,257,263,
%T 269,271,347,349,367,379,457,461,487,577,607,673,701,761,797,809,907,
%U 911,967,983,1019,1031,1033,1049,1063,1097,1103,1109,1283,1303,1423
%N Primes p such that the p-th squarefree number is prime.
%t Module[{nn=2500,sqf},sqf=Select[Range[nn],SquareFreeQ];Select[Prime[ Range[ PrimePi[Length[sqf]]]],PrimeQ[sqf[[#]]]&]] (* _Harvey P. Dale_, Jul 28 2021 *)
%o (PARI) lista(nn) = my(sqfs = select(n->issquarefree(n), vector(nn, i, i))); forprime(p = 2, #sqfs, if (isprime(sqfs[p]), print1(p, ", "))) \\ _Michel Marcus_, Sep 11 2013
%Y Cf. A005117.
%Y Subsequence of A071403.
%K nonn
%O 1,1
%A _Irina Gerasimova_, Sep 10 2013
%E Corrected by _Harvey P. Dale_, Jul 28 2021
|
