%I #24 Sep 08 2022 08:45:07
%S 8,12,18,20,28,30,42,44,50,52,66,68,70,76,78,92,98,102,110,114,116,
%T 124,130,138,148,154,164,170,172,174,182,186,188,190,212,222,230,236,
%U 238,242,244,246,258,266,268,282,284,286,290,292,310,316,318,322,332,338
%N Even numbers with exactly 3 prime factors (counted with multiplicity).
%C Twice the semiprime numbers. - _Juri-Stepan Gerasimov_, Jun 01 2010
%H Vincenzo Librandi, <a href="/A075818/b075818.txt">Table of n, a(n) for n = 1..2626</a>
%F a(n)=2*A001358(n). - _Juri-Stepan Gerasimov_, Jun 01 2010
%e 28=2^2*7, 30=2*3*5 and 42=2*3*7 are even and are products of exactly 3 primes.
%p ts_bo3_sod := proc(n); if (numtheory[bigomega](n)=3 and type(n,even)='true') then RETURN(n); fi end: abo3sod := [seq(ts_bo3_sod(i), i=1..2300)]: abo3sod;
%t Select[Range[100], Plus@@Last/@FactorInteger[#]==2&] 2 (* _Vincenzo Librandi_, Nov 10 2018 *)
%t Select[Range[2,400,2],PrimeOmega[#]==3&] (* _Harvey P. Dale_, Oct 15 2021 *)
%o (PARI) list(lim)=my(v=List()); forprime(p=2, lim\4, forprime(q=2, min(lim\p\2,p), listput(v, 2*p*q))); Set(v) \\ _Charles R Greathouse IV_, Aug 29 2017
%o (Magma) [2*n: n in [2..200] | &+[d[2]: d in Factorization(n)] eq 2]; // _Vincenzo Librandi_ Nov 10 2018
%Y Cf. A046470, A053858.
%K easy,nonn
%O 1,1
%A _Jani Melik_, Oct 13 2002
%E Edited by _Dean Hickerson_, Oct 21 2002