cp's OEIS Frontend

A346990 Numbers occurring as divisors of 2^k + 3^k, k > 0.

%I A346990 #16 Dec 10 2022 10:47:01
%S A346990 1,5,7,11,13,17,25,31,35,37,41,49,55,59,61,73,77,79,83,89,97,103,107,
%T A346990 109,113,121,125,127,131,137,149,151,155,157,169,173,175,179,181,193,
%U A346990 199,217,223,227,229,233,241,245,251,257,271,275,277,281,289,295,313
%N A346990 Numbers occurring as divisors of 2^k + 3^k, k > 0.
%C A346990 If n is a term, then so are all divisors of n. - _Robert Israel_, Dec 08 2022
%H A346990 Robert Israel, <a href="/A346990/b346990.txt">Table of n, a(n) for n = 1..10000</a>
%p A346990 filter:= proc(n) local v;
%p A346990    if igcd(n,6) <> 1 then return false fi;
%p A346990    q:= 3/2 mod n;
%p A346990    traperror(NumberTheory:-ModularLog(-1,q,n)) <> lasterror
%p A346990 end proc:
%p A346990 filter(1):= true:
%p A346990 select(filter, [$1..400]); # _Robert Israel_, Dec 08 2022
%Y A346990 Cf. A007689, A005056.
%K A346990 nonn
%O A346990 1,2
%A A346990 _Hugo Pfoertner_, Aug 11 2021