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

1,2

Links

Table of n, a(n) for n=1..55.

Formula

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

Prog

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

Crossrefs

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

Sequence in context: A056176 A143831 A087072 * A022825 A225086 A062413

Adjacent sequences: A234849 A234850 A234851 * A234853 A234854 A234855

Keyword

nonn

Author

M. F. Hasler, Dec 31 2013

Status

approved