OFFSET
1,1
EXAMPLE
37 is such a prime as the 37th composite number is 54 and Omega(54) = Omega(2^1*3^3) = 4, which is composite. Likewise 71, as c(71) = 96, and Omega(96) = Omega(2^5*3^1) = 6 which is composite. 113 is not such a prime, as Omega(c(113)) = Omega(148) = Omega(2^2*37^1) =3 which is prime.
MAPLE
with(numtheory): composites := remove(isprime, [$2..3000]):
A155087:= select(x -> isprime(x) and not isprime(bigomega(composites[x])), [$2..2000]);
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Jan 20 2009, Jan 28 2009
EXTENSIONS
Corrected and edited by D. S. McNeil, Mar 19 2009
STATUS
approved