A092953 - OEIS

%I #13 Dec 05 2022 04:42:05

%S 0,0,1,1,1,1,0,2,1,2,1,3,0,2,1,3,1,3,0,3,1,2,0,6,0,4,1,3,1,6,0,3,0,4,

%T 1,6,0,4,1,5,1,8,0,4,1,4,0,7,0,6,1,4,0,9,0,8,1,4,1,11,0,5,0,5,1,11,0,

%U 6,1,8,1,9,0,4,0,7,1,11,0,7,1,4,0,13,0,7,1,5,0,15,0,7,0,8,1,13,0,8,1,9,1,11

%N Number of primes of the form n+p, where p is a prime < n.

%C Might be called the additive primability of n.

%C a(A007921(n))=0; for n > 2: a(A030173(n)) > 0 and a(A040976(n)) = 1. - _Reinhard Zumkeller_, Nov 10 2012

%H Reinhard Zumkeller, <a href="/A092953/b092953.txt">Table of n, a(n) for n = 1..10000</a>

%e a(26) = 4: the primes are 29, 31, 37 and 43.

%o (PARI) for(n=1,105,c=0;forprime(p=2,n-1,if(isprime(n+p),c++));print1(c,","))

%o (Haskell)

%o a092953 n = sum $

%o    zipWith (\u v -> a010051' u * a010051' v) [1 .. n - 1] [n + 1 ..]

%o -- _Reinhard Zumkeller_, Nov 10 2012

%Y Cf. A092954.

%Y Cf. A061357.

%K nonn

%O 1,8

%A _Amarnath Murthy_, Mar 24 2004

%E More terms from _Klaus Brockhaus_ and Mohammed Bouayoun (bouyao(AT)wanadoo.fr), Mar 25 2004