

A280389


Odd semiprimes that can be represented as 2p+3q, where p and q are primes.


3



15, 21, 25, 35, 39, 49, 55, 57, 65, 77, 85, 91, 93, 95, 115, 119, 121, 129, 133, 143, 145, 155, 161, 169, 183, 185, 187, 203, 205, 209, 215, 217, 219, 221, 235, 247, 253, 259, 265, 287, 289, 295, 299, 301, 305, 309, 319, 323, 327, 329, 335, 341, 355, 361, 365, 371, 377, 391, 395, 403
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OFFSET

1,1


LINKS



MAPLE

N:= 10^3: # to get all terms <= N
Primes:= select(isprime, [2, seq(i, i=3..N/2, 2)]):
Cands:= select(t > t::odd and t <= N, {seq(seq(2*p+3*q, p=Primes), q=Primes)}):
sort(convert(select(numtheory:bigomega=2, Cands), list)); # Robert Israel, Jan 09 2017


CROSSREFS

Cf. A280405 (odd semiprimes which can NOT be represented as 2p+3q, where p and q are prime).


KEYWORD

nonn


AUTHOR



STATUS

approved



