OFFSET
1,2
COMMENTS
Conjecture: For k > 1, k^(m + 1) == -1 (mod m) has an infinite number of positive solutions.
Terms cannot be a multiple of the following primes below 100: 2, 3, 5, 7, 11, 19, 23, 29, 31, 43, 47, 53, 59, 67, 71, 79, 83. - Giovanni Resta, Nov 09 2019
PROG
(Magma) [n + 1: n in [0..20000000] | Modexp(6, n + 2, n + 1) eq n];
(PARI) isok(m) = Mod(6, m)^(m+1) == -1; \\ Jinyuan Wang, Nov 16 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Nov 08 2019
EXTENSIONS
a(5)-a(21) from Giovanni Resta, Nov 09 2019
STATUS
approved