OFFSET
1,1
COMMENTS
A350705 is a subsequence.
LINKS
Karl-Heinz Hofmann, Table of n, a(n) for n = 1..10000
EXAMPLE
a(5) = 12 = 2 * 2 * 3 and {2, 3} are not in A005385.
MATHEMATICA
Select[Range[200], CompositeQ[#] && AllTrue[FactorInteger[#][[;; , 1]], ! PrimeQ[(#1 - 1)/2] &] &] (* Amiram Eldar, Feb 20 2022 *)
PROG
(PARI) isok(m) = if ((m>1) && !isprime(m), !#select(x->isprime((x-1)\2), factor(m)[, 1]));
(Python)
from sympy import primefactors, isprime
print([n for n in range(4, 172) if not isprime(n) and all(not isprime((p-1)//2) for p in primefactors(n))])
CROSSREFS
KEYWORD
nonn
AUTHOR
Karl-Heinz Hofmann, Feb 20 2022
STATUS
approved