OFFSET
1,2
COMMENTS
The following are equivalent.
1. n is in the sequence.
2. prime(n) is in the sequence.
3. n is a product of prime numbers that are already in the sequence and that are either all equal or all different.
MATHEMATICA
primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
go[n_]:=And[Or[SameQ@@primeMS[n], UnsameQ@@primeMS[n]], And@@go/@primeMS[n]]
Select[Range[100], go]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jul 05 2018
STATUS
approved