A225587 a(n) is the smallest prime of the form prime(n)*q + prime(n) + q, where q is an odd prime.

11, 23, 23, 31, 47, 83, 71, 79, 191, 179, 127, 151, 167, 263, 191, 431, 239, 743, 271, 431, 443, 479, 503, 359, 587, 1223, 1871, 431, 439, 683, 6143, 1583, 827, 839, 599, 607, 631, 983, 2351, 2087, 719, 727, 1151, 1163, 1187, 2399, 2543, 2687, 911, 919

Offset: 1

Author

John-Å. W. Olsen, May 11 2013

Keywords

• nonn
• easy

Comments

The odd primes q minimizing prime(n)*q + prime(n) + q are listed in A225581.

Examples

			a(1) = 11 because prime(1) = 2 and the minimal prime of the form 2*q+2+q with q an odd prime is 11 = 2*3+2+3.
		

Links

• John-Å. W. Olsen, Table of a(n), for n = 1..1000

Crossrefs

Cf. A225581, A000040.

Programs

Mathematica

a[n_] := Block[{q = 3, v, p = Prime@n},While[! PrimeQ[v = p q + p + q], q = NextPrime@q]; v]; Array[a, 50] (* Giovanni Resta, May 11 2013 *)

Formula

a(n) = (1+prime(n))*A225581(n) + prime(n).

Extensions

a(26)-a(50) from Giovanni Resta, May 11 2013