A346992 Numbers occurring as divisors of 3^k + 5^k.

1, 2, 4, 8, 13, 17, 19, 23, 26, 29, 31, 34, 37, 38, 41, 46, 47, 53, 58, 62, 73, 74, 76, 79, 82, 83, 89, 92, 94, 97, 101, 106, 107, 113, 124, 137, 139, 146, 149, 151, 152, 157, 158, 166, 167, 169, 178, 184, 188, 193, 194, 199, 202, 211, 212, 214, 221, 226, 227

Offset: 1

Author

Hugo Pfoertner, Aug 11 2021

Keywords

• nonn

Comments

If n is a term, then so are all divisors of n. - Robert Israel, Dec 08 2022

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A074606, A081186.

Programs

Maple

filter:= proc(n) local v;
   if igcd(n,15) <> 1 then return false fi;
   q:= 5/3 mod n;
   traperror(NumberTheory:-ModularLog(-1,q,n)) <> lasterror
end proc:
filter(1):= true:
select(filter, [$1..300]); # Robert Israel, Dec 08 2022