A172366 Number of partitions of prime(n) into the sum of two semiprimes.

0, 0, 0, 0, 0, 1, 0, 2, 1, 2, 3, 2, 2, 4, 4, 3, 5, 6, 4, 6, 5, 5, 7, 4, 7, 6, 7, 7, 5, 5, 8, 8, 8, 8, 9, 10, 9, 7, 13, 10, 10, 11, 13, 10, 10, 10, 11, 15, 18, 13, 10, 13, 14, 16, 12, 18, 12, 15, 12, 11

Offset: 1

Author

Juri-Stepan Gerasimov, Nov 20 2010

Keywords

• nonn

Examples

			a(8)=2 because prime(8)=19=4(semiprime)+15(semiprime)=9(semiprime)+10(semiprime).
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A129363, A175933,

Programs

Mathematica

Table[Total[If[PrimeOmega[#]=={2,2},1,0]&/@Table[{x-n,n},{n,x/2}]],{x, Prime[ Range[60]]}] (* Harvey P. Dale, Dec 21 2015 *)

Formula

a(n) = A072931(A000040(n)).

Extensions

Corrected and extended by D. S. McNeil, Nov 20 2010