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Product of a prime number p and the number of primes smaller than p.
5

%I #19 Sep 16 2014 03:17:19

%S 0,3,10,21,44,65,102,133,184,261,310,407,492,559,658,795,944,1037,

%T 1206,1349,1460,1659,1826,2047,2328,2525,2678,2889,3052,3277,3810,

%U 4061,4384,4587,5066,5285,5652,6031,6346,6747,7160,7421,8022,8299,8668,8955,9706

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

%H Jens Kruse Andersen, <a href="/A117495/b117495.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = (n-1)*prime(n). - _Zak Seidov_, Aug 15 2010

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

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

%t Table[(n - 1)Prime[n], {n, 60}] (* _Zak Seidov_, Aug 15 2010 *)

%o (PARI) a(n)=prime(n)*(n-1) \\ _Charles R Greathouse IV_, Sep 15 2014

%Y Cf. A000720, A033286, A036689.

%K nonn,easy

%O 1,2

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

%E a(31) corrected by _Jens Kruse Andersen_, Sep 15 2014