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A337828
Odd integers k such that 3^((k-1)/2) + 1 == 0 (mod k*(k-1)/2).
0
5, 101, 62501, 1020101, 31562501, 139476101, 637562501, 789062501, 985502501, 2656262501, 7455062501, 19726562501, 53662562501
OFFSET
1,1
COMMENTS
Computed terms are prime.
MATHEMATICA
Select[Range[3, 3*10^7, 2], PowerMod[3, (# - 1)/2, (t = #*(# - 1)/2)] == t - 1 &] (* Amiram Eldar, Sep 24 2020 *)
CROSSREFS
Cf. A337818.
Sequence in context: A113073 A349045 A337831 * A275749 A057207 A124986
KEYWORD
nonn,more
AUTHOR
Benoit Cloitre, Sep 24 2020
EXTENSIONS
a(7)-a(13) from Amiram Eldar, Sep 25 2020
STATUS
approved