

A172366


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


1



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
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OFFSET

1,8


LINKS

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


FORMULA

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


EXAMPLE

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


MATHEMATICA

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


CROSSREFS

Cf. A129363, A175933,
Sequence in context: A320387 A304707 A112218 * A132148 A237829 A159974
Adjacent sequences: A172363 A172364 A172365 * A172367 A172368 A172369


KEYWORD

nonn


AUTHOR

JuriStepan Gerasimov, Nov 20 2010


EXTENSIONS

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


STATUS

approved



