A190353 Goldbach conjecture: number of decompositions of n into an unordered sum of two odd primes (if n even) or three odd primes (if n odd).

0, 0, 0, 0, 0, 1, 0, 1, 1, 2, 1, 1, 2, 2, 2, 2, 3, 2, 3, 2, 4, 3, 4, 3, 5, 3, 6, 2, 7, 3, 6, 2, 8, 4, 7, 4, 9, 2, 10, 3, 10, 4, 10, 3, 11, 4, 12, 5, 12, 4, 14, 3, 16, 5, 14, 3, 16, 4, 16, 6, 16, 3, 18, 5, 20, 6, 20, 2, 20, 5, 21, 6, 21, 5, 21, 5, 27, 7, 24

Offset: 1

Author

Daniel Forgues, May 09 2011

Keywords

• nonn

Comments

This sequence differs from A083338 because A083338 allows 2 as a prime.

Links

• Daniel Forgues, Table of n, a(n) for n = 1..20000
• OEIS Wiki, Goldbach conjecture

Crossrefs

Cf. A002375, A007963, A083338.

Formula

a(2n) = A002375(n) and a(2n+1) = A007963(n).