OFFSET
1,2
COMMENTS
For any j>=0, 5*A003598(j) is a term of the sequence. - Benoit Cloitre, Mar 08 2002
From Robert Israel, Jun 29 2017: (Start)
This is a semigroup: if m and n are in the sequence, then so is m*n.
If n is in the sequence and is divisible by prime p, then so is p*n.
The only prime power in the sequence is 5.
Conjecture: Every member of the sequence except 1 is of the form p*m where p is prime and m is in the sequence. (End)
LINKS
Robert Israel and Giovanni Resta, Table of n, a(n) for n = 1..1000 (first 205 terms from Robert Israel)
MAPLE
select(t -> 3 &^ t + 2 &^ t mod t = 0, [seq(i, i=1..10^6, 2)]); # Robert Israel, Jun 29 2017
PROG
(PARI) isok(n) = ((3^n+2^n) % n) == 0; \\ Michel Marcus, Jun 29 2017
(PARI) isok(n)=(Mod(2, n)^n+Mod(3, n)^n)==0; \\ significantly more efficient
for(n=1, 10^6, if(isok(n), print1(n, ", "))); \\ Joerg Arndt, Aug 13 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved