OFFSET
1,1
COMMENTS
A subset of A057949, removing terms that are a multiple of a smaller term.
Cubefree numbers with exactly 4 prime factors, all congruent to 3 mod 4. - Charlie Neder, Nov 26 2018
LINKS
Eric M. Schmidt, Table of n, a(n) for n = 1..10000
EXAMPLE
441 is in S = {1, 5, 9, ... 4i+1, ...}, 441 = 9*49 = 21^2, 9, 21 and 49 as S-primes (A057948). 441 is primitive because it is not divisible by any smaller numbers with more than 1 factorization into S-primes. Multiples of 441 within S are not primitive.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jud McCranie, Oct 14 2000
EXTENSIONS
Definition edited and offset corrected by Eric M. Schmidt, Dec 11 2016
STATUS
approved