OFFSET
1,2
LINKS
Jinyuan Wang, Table of n, a(n) for n = 1..5000 (first 500 terms from Seiichi Manyama)
MATHEMATICA
Select[Range@ 14000, Divisible[5^# + 1, #] &] (* Michael De Vlieger, Oct 10 2016 *)
Select[Range[15000], PowerMod[5, #, #]==#-1&] (* Harvey P. Dale, Aug 11 2024 *)
PROG
(PARI) isok(n) = Mod(5, n)^n == -1; \\ Michel Marcus, Oct 11 2016
(Magma) [n: n in [1..10^5] | Modexp(5, n, n)+1 eq n]; // Jinyuan Wang, Dec 29 2018
(Python)
for n in range(1, 10**5):
if pow(5, n, n)+1 == n: print(n, end=', ') # Stefano Spezia, Dec 30 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved