A062311 Number of ways writing n! as a sum of two primes.

0, 0, 0, 1, 3, 12, 39, 184, 951, 5531, 38713, 346207, 3130812, 34444964, 382437428, 4637235145

Offset

0,5

Comments

Number of unordered pairs of primes (p,q) such that n! = p + q.

Links

Table of n, a(n) for n=0..15.

Formula

In other words, a(n) = A061358(n!) = number of prime+prime partitions of n!.

Example

n = 4: 4! = 24 = 5+19 = 7+17 = 11+13 so a(4) = 3.

Crossrefs

Cf. A061358, A000142. See A140088 for a variant.

Sequence in context: A183366 A122994 A271218 * A303348 A237036 A034956

Adjacent sequences: A062308 A062309 A062310 * A062312 A062313 A062314

Keyword

nonn,more

Author

Labos Elemer, Jul 05 2001

Extensions

a(9)-a(12) from Hans Havermann, Apr 29 2008

a(13) from Graeme McRae, May 02 2008

a(14)-a(15) from Hans Havermann, Dec 21 2008

Status

approved