A179893 a(n) = 3/2 * (prime(n)-1).

3, 6, 9, 15, 18, 24, 27, 33, 42, 45, 54, 60, 63, 69, 78, 87, 90, 99, 105, 108, 117, 123, 132, 144, 150, 153, 159, 162, 168, 189, 195, 204, 207, 222, 225, 234, 243, 249, 258, 267, 270, 285, 288, 294, 297, 315, 333, 339, 342, 348, 357, 360, 375, 384, 393, 402, 405

Offset: 2

Author

Odimar Fabeny, Jul 30 2010, Aug 02 2010

Keywords

• easy
• nonn

Examples

			For n=4, the fourth prime is 7, so a(4) = (3/2) * (7 - 1) = 9. Note that since the sequence starts at n=2, prime(n) is odd, so a(n) is an integer. - _Michael B. Porter_, Jul 19 2016
		

Links

• G. C. Greubel, Table of n, a(n) for n = 2..1000

Crossrefs

Cf. A000040, A179545.

Programs

Magma

[3/2*(NthPrime(n)-1): n in [2..60]]; // Vincenzo Librandi, Jun 18 2016

Mathematica

Table[(3/2)*(Prime[n] - 1), {n,2,100}] (* G. C. Greubel, Jun 17 2016 *)

PARI

a(n)=prime(n)\2*3 \\ Charles R Greathouse IV, May 19 2011

Formula

A179545 / prime(n).

a(n) = 3*A005097(n-1). - R. J. Mathar, Aug 15 2010

Extensions

More terms from R. J. Mathar, Aug 15 2010