OFFSET
1,1
COMMENTS
All terms are congruent to 9 or 11 (mod 18).
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..6115
EXAMPLE
8127 is in sequence because 8127+2 = 11*739, 8127+4 = 47*173, 8127+6 = 3*2711, 8127+8 = 5*1627, 8127+10 = 79*103, 8127+12 = 3*2713, 8127+14 = 7*1163 are all semiprime.
MATHEMATICA
Select[Range[400000], Union[PrimeOmega[# + {2, 4, 6, 8, 10, 12, 14}]] == {2} &]
PROG
(Magma) IsSemiprime := func<n | &+[m[2]: m in Factorization(n)] eq 2>; [n: n in [2..700000] | forall{i: i in [2..14 by 2] | IsSemiprime(n+i)}];
CROSSREFS
KEYWORD
nonn
AUTHOR
Vincenzo Librandi, Feb 17 2016
STATUS
approved