OFFSET
1,1
COMMENTS
Also numbers n whose median prime factor is a prime factor of n.
EXAMPLE
The prime factorization of 90 is 2*3*3*5, with middle parts (3,3), so 90 is in the sequence.
MATHEMATICA
prifacs[n_]:=If[n==1, {}, Flatten[ConstantArray@@@FactorInteger[n]]];
Select[Range[2, 100], MemberQ[prifacs[#], Median[prifacs[#]]]&]
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 10 2023
STATUS
approved