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

1,2

Links

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

Formula

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

Example

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

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 *)

Prog

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

Crossrefs

Cf. A000720, A033286, A036689.

Sequence in context: A210980 A207380 A268348 * A007687 A330273 A335666

Adjacent sequences: A117492 A117493 A117494 * A117496 A117497 A117498

Keyword

nonn,easy

Author

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

Extensions

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

Status

approved