OFFSET
1,1
LINKS
Paolo Xausa, Table of n, a(n) for n = 1..10000
FORMULA
a(n) == 7 (mod 12) for n>1. - Hugo Pfoertner, Jul 24 2024
MATHEMATICA
Select[Prime[Range[1000]], PowerMod[# - 1, #, 2*# - 1] == # &] (* Paolo Xausa, Jul 24 2024 *)
PROG
(Magma) [p: p in PrimesUpTo(10^4) | (p-1)^p mod (2*p-1) eq p];
(PARI) list(lim)=my(v=List([3])); forprimestep(p=7, lim\1, 12, if(Mod(p-1, 2*p-1)^p==p, listput(v, p))); Vec(v) \\ Charles R Greathouse IV, Jul 23 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Jul 23 2024
STATUS
approved