A071149 - OEIS

%I #29 Oct 08 2017 17:33:10

%S 1,9,15,17,53,55,61,65,71,75,95,115,117,137,141,143,155,183,191,203,

%T 249,273,275,283,291,305,339,341,377,409,411,415,435,439,449,483,495,

%U 497,509,525,583,599,605,621,633,637,643,645,671,675,709,713,715,727

%N Numbers n such that the sum of the first n odd primes (A071148) is prime; analogous to A013916.

%H T. D. Noe, <a href="/A071149/b071149.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = pi(A071150(n)). - _Charles R Greathouse IV_, May 13 2015

%p Primes:= select(isprime, [seq(2*i+1,i=1..10^4)]):

%p L:= ListTools:-PartialSums(Primes):

%p select(i -> isprime(L[i]), [$1..nops(L)]); # _Robert Israel_, May 19 2015

%t Position[Accumulate@ Prime@ Range[2, 750], _?(PrimeQ@# &)] // Flatten (* _Robert G. Wilson v_, May 19 2015, after _Harvey P. Dale_ in A013916 *)

%o (PARI) s=n=0; forprime(p=3,1e4, n++; if(isprime(s+=p), print1(n", "))) \\ _Charles R Greathouse IV_, May 13 2015

%Y Cf. A007504, A013916, A013917, A013918, A065091, A071148, A071150, A089228.

%K nonn

%O 1,2

%A _Labos Elemer_, May 13 2002