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A346992 Numbers occurring as divisors of 3^k + 5^k. 1

%I #11 Dec 09 2022 15:42:48

%S 1,2,4,8,13,17,19,23,26,29,31,34,37,38,41,46,47,53,58,62,73,74,76,79,

%T 82,83,89,92,94,97,101,106,107,113,124,137,139,146,149,151,152,157,

%U 158,166,167,169,178,184,188,193,194,199,202,211,212,214,221,226,227

%N Numbers occurring as divisors of 3^k + 5^k.

%C If n is a term, then so are all divisors of n. - _Robert Israel_, Dec 08 2022

%H Robert Israel, <a href="/A346992/b346992.txt">Table of n, a(n) for n = 1..10000</a>

%p filter:= proc(n) local v;

%p if igcd(n,15) <> 1 then return false fi;

%p q:= 5/3 mod n;

%p traperror(NumberTheory:-ModularLog(-1,q,n)) <> lasterror

%p end proc:

%p filter(1):= true:

%p select(filter, [$1..300]); # _Robert Israel_, Dec 08 2022

%Y Cf. A074606, A081186.

%K nonn

%O 1,2

%A _Hugo Pfoertner_, Aug 11 2021

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Last modified April 20 00:26 EDT 2024. Contains 371798 sequences. (Running on oeis4.)