OFFSET
1,2
COMMENTS
A multiplicative semigroup: if m and n are in the sequence, then so is m*n. - Antti Karttunen, Jul 02 2024
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1600
MATHEMATICA
DeleteCases[3 Range[0, 300] + 1, _?PrimeQ]
PROG
(Magma) [n: n in [1..400 by 3] | not IsPrime(n)];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Aug 31 2017
STATUS
approved