A228727 Smallest prime of the form k*prime(n) + prime(k*n).

7, 13, 23, 131, 179, 229, 283, 337, 107, 641, 317, 163, 643, 193, 1949, 523, 257, 2053, 1021, 1933, 2477, 773, 811, 401, 929, 6379, 457, 6197, 5701, 1747, 547, 1949, 1291, 2083, 647, 661, 2341, 709, 1579, 2549, 2633, 1721, 4909, 2851, 857, 877, 5441, 4441

Offset: 1

Author

Irina Gerasimova, Aug 31 2013, Sep 04 2013

Keywords

• nonn

Comments

Primes of the form 2*prime(n) + prime(2*n): 7, 13, 23, 107, 163, 193, 257, 401, 457, 547, 647, 661, 709, 857, 877, 1201,...

Examples

			a(1)=7 because 7 is prime and 2*prime(1) + prime(2*1) = 4 + 3 = 7.
a(2) = 13 because 13 is prime and 2*prime(2) + prime(2*2) = 6 + 7 = 13.
		

Crossrefs

Cf. A095304.

Programs

Mathematica

Table[k = 1; While[p = k*Prime[n] + Prime[k*n]; ! PrimeQ[p], k++]; p, {n, 100}] (* T. D. Noe, Sep 03 2013 *)

Extensions

Corrected by R. J. Mathar, Sep 02 2013