A096064 -id:A096064 - cp's OEIS frontend

A192611 Primes prime(k) such that prime(k)*k+1 is also prime.

2, 3, 7, 13, 89, 113, 151, 181, 359, 433, 521, 541, 641, 701, 719, 827, 953, 1033, 1277, 1301, 1439, 1877, 2069, 2111, 2143, 2267, 2357, 2423, 2791, 2801, 2861, 2887, 3191, 3251, 3313, 3557, 3643, 3739, 3797, 3821, 3863, 3931, 3947, 4021, 4447

Offset: 1

Andrea Raffetti, Jul 05 2011

nonn

Primes p such that p*pi(p)+1 is prime (see Crossrefs).

			13 is in the list because, being the 6th prime, 13*6+1=79 is prime.

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Cf. A096064, A086172.
Cf. A000040 The prime numbers.
Cf. A000720 pi(n), the number of primes <= n.

[ NthPrime(n): n in [1..650] | IsPrime(NthPrime(n)*n+1) ]; // Bruno Berselli, Jul 05 2011

Select[Prime[Range[700]],PrimeQ[# PrimePi[#]+1]&] (* Harvey P. Dale, May 28 2012 *)

k=0;forprime(p=2,1e4,if(isprime(k++*p+1),print1(p", "))) \\ Charles R Greathouse IV, Jul 05 2011

A096065 Let p(k) = k-th prime; sequence gives primes q of the form q = k*p(k) - 1 for some k.

Original entry on oeis.org

5, 151, 443, 601, 1097, 3389, 13553, 20921, 25847, 32719, 41669, 46153, 56813, 66109, 84691, 119087, 129449, 150559, 188857, 201847, 206273, 240173, 266863, 271109, 310577, 318751, 346553, 395749, 430819, 446951, 451933, 507079, 645527

Offset: 0

Alonso del Arte, Jul 20 2004

nonn

			a(3)=443 because the twelfth prime is 37 and 12 * 37 - 1 = 443.

Cf. A086173, A096064.

Select[Table[Prime[n]*n - 1, {n, 320}], PrimeQ]

cp's OEIS Frontend

A192611 Primes prime(k) such that prime(k)*k+1 is also prime.

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