A117495 Product of a prime number p and the number of primes smaller than p.

0, 3, 10, 21, 44, 65, 102, 133, 184, 261, 310, 407, 492, 559, 658, 795, 944, 1037, 1206, 1349, 1460, 1659, 1826, 2047, 2328, 2525, 2678, 2889, 3052, 3277, 3810, 4061, 4384, 4587, 5066, 5285, 5652, 6031, 6346, 6747, 7160, 7421, 8022, 8299, 8668, 8955, 9706

Offset: 1

Author

Luc Stevens (lms022(AT)yahoo.com), Apr 25 2006

Keywords

• nonn
• easy

Examples

			a(9) = 184 because (1) the 9th prime number is 23, (2) there are 8 primes smaller than 23 and (3) 23*8 = 184.
		

Links

• Jens Kruse Andersen, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000720, A033286, A036689.

Programs

Maple

with(numtheory):a:=n->sum(ithprime(n), j=2..n):seq(a(n), n=1..47); # Zerinvary Lajos, Aug 24 2008

Mathematica

Table[(n - 1)Prime[n], {n, 60}] (* Zak Seidov, Aug 15 2010 *)

PARI

a(n)=prime(n)*(n-1) \\ Charles R Greathouse IV, Sep 15 2014

Formula

a(n) = (n-1)*prime(n). - Zak Seidov, Aug 15 2010

Extensions

a(31) corrected by Jens Kruse Andersen, Sep 15 2014