OFFSET
1,2
COMMENTS
Complement of A182800.
EXAMPLE
A167171=(2,3,5,6,7,10,11,13,14,15,17,19,21,22,23,...) consists of primes and products p*q of distinct primes.
a(1)=1 because 2 is in position 1;
a(4)=5 because 7 is in position 5.
PROG
(PARI) lista(nn) = {nb = 0; for (n=1, nn, if (numdiv(n) == 2*omega(n), nb++; if (isprime(n), print1(nb, ", ")); ); ); } \\ Michel Marcus, May 15 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Dec 03 2010
STATUS
approved