OFFSET
1,8
COMMENTS
Might be called the additive primability of n.
a(A007921(n))=0; for n > 2: a(A030173(n)) > 0 and a(A040976(n)) = 1. - Reinhard Zumkeller, Nov 10 2012
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
EXAMPLE
a(26) = 4: the primes are 29, 31, 37 and 43.
PROG
(PARI) for(n=1, 105, c=0; forprime(p=2, n-1, if(isprime(n+p), c++)); print1(c, ", "))
(Haskell)
a092953 n = sum $
zipWith (\u v -> a010051' u * a010051' v) [1 .. n - 1] [n + 1 ..]
-- Reinhard Zumkeller, Nov 10 2012
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Mar 24 2004
EXTENSIONS
More terms from Klaus Brockhaus and Mohammed Bouayoun (bouyao(AT)wanadoo.fr), Mar 25 2004
STATUS
approved