OFFSET
1,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..10000
EXAMPLE
1 is a product of zero primes so is in the sequence.
6 = 2 * 3 is a product of two primes so is not in the sequence.
12 = 2 * 2 * 3 is a product of three primes so is in the sequence.
MAPLE
a:= proc(n) option remember; local k; for k
from 1+`if`(n=1, 0, a(n-1)) while not
numtheory[bigomega](k) in {0, 1, 3} do od; k
end:
seq(a(n), n=1..70); # Alois P. Heinz, Jan 15 2018
MATHEMATICA
Select[Range[200], MemberQ[{0, 1, 3}, PrimeOmega[#]]&]
PROG
(PARI) is(n) = my(v=[0, 1, 3]); #setintersect([bigomega(n)], v)==1 \\ Felix Fröhlich, Jan 15 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jan 14 2018
STATUS
approved