A136026 Smallest prime of the form (2n+1)p + 2n with p prime.

11, 19, 41, 53, 43, 103, 59, 67, 113, 83, 137, 149, 107, 173, 433, 131, 139, 443, 233, 163, 257, 179, 281, 293, 1019, 211, 439, 227, 353, 487, 251, 389, 401, 827, 283, 1021, 449, 307, 631, 647, 331, 509, 347, 1601, 727, 557, 379, 1163, 593, 2423, 617, 419, 641

Offset: 1

Author

Artur Jasinski, Dec 10 2007

Keywords

• nonn
• easy

Comments

The associated p are in A136027.

Examples

			a(1)=11 because 11 is smallest prime p such that (p-2)/3 is prime.
a(2)=19 because 19 is smallest prime p such that (p-4)/5 is prime.
a(3)=41 because 41 is smallest prime p such that (p-6)/7 is prime.
		

Links

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

Crossrefs

Cf. A136019, A136020, A136027.

Programs

Mathematica

a = {}; Do[k = 1; While[ !PrimeQ[(Prime[k] - 2n)/(2n + 1)], k++ ]; AppendTo[a, Prime[k]], {n, 1, 100}]; a

PARI

a(n)=my(t);forprime(p=2,,if(isprime(t=2*n*(p+1)+p),return(t))) \\ Charles R Greathouse IV, Mar 21 2013

Extensions

Edited by R. J. Mathar, May 17 2009