A234852 Indices k of primes p=prime(k) such that prime(p)-p+1 is prime.

1, 2, 3, 4, 6, 7, 9, 11, 13, 14, 18, 20, 23, 24, 27, 29, 34, 36, 40, 42, 46, 47, 48, 53, 58, 59, 60, 62, 63, 64, 66, 68, 70, 71, 73, 90, 95, 100, 103, 105, 110, 121, 122, 127, 128, 132, 133, 134, 141, 143, 144, 153, 155, 156, 162

Offset: 1

Author

M. F. Hasler, Dec 31 2013

Keywords

• nonn

Crossrefs

Cf. A000040, A000720, A014692, A234850, A234851.

Programs

Mathematica

Select[Range[200],PrimeQ[Prime[Prime[#]]-Prime[#]+1]&] (* Harvey P. Dale, Jul 14 2024 *)

PARI

for(k=1,999,isprime(prime(p=prime(k))-p+1)&&print1(k","))

Formula

a(n) = PrimePi(A234695(n)), PrimePi = A000720.