cp's OEIS Frontend

A092953 Number of primes of the form n+p, where p is a prime < n.

%I A092953 #13 Dec 05 2022 04:42:05
%S A092953 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 A092953 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 A092953 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 A092953 Number of primes of the form n+p, where p is a prime < n.
%C A092953 Might be called the additive primability of n.
%C A092953 a(A007921(n))=0; for n > 2: a(A030173(n)) > 0 and a(A040976(n)) = 1. - _Reinhard Zumkeller_, Nov 10 2012
%H A092953 Reinhard Zumkeller, <a href="/A092953/b092953.txt">Table of n, a(n) for n = 1..10000</a>
%e A092953 a(26) = 4: the primes are 29, 31, 37 and 43.
%o A092953 (PARI) for(n=1,105,c=0;forprime(p=2,n-1,if(isprime(n+p),c++));print1(c,","))
%o A092953 (Haskell)
%o A092953 a092953 n = sum $
%o A092953    zipWith (\u v -> a010051' u * a010051' v) [1 .. n - 1] [n + 1 ..]
%o A092953 -- _Reinhard Zumkeller_, Nov 10 2012
%Y A092953 Cf. A092954.
%Y A092953 Cf. A061357.
%K A092953 nonn
%O A092953 1,8
%A A092953 _Amarnath Murthy_, Mar 24 2004
%E A092953 More terms from _Klaus Brockhaus_ and Mohammed Bouayoun (bouyao(AT)wanadoo.fr), Mar 25 2004