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A015953
Numbers k such that k | 6^k + 1.
10
1, 7, 49, 203, 343, 1379, 1421, 2401, 5887, 9653, 9947, 11977, 16807, 39991, 41209, 67571, 69629, 83839, 117649, 170723, 271663, 279937, 288463, 347333, 472997, 487403, 586873, 706643, 823543, 1159739, 1195061, 1901641, 1959559, 2019241, 2359469, 2431331
OFFSET
1,2
LINKS
MATHEMATICA
Select[Range[2000000], PowerMod[6, #, #]==#-1&] (* Harvey P. Dale, Aug 28 2012 *)
CROSSREFS
Solutions to b^k == -1 (mod k): A006521 (b=2), A015949 (b=3), A015950 (b=4), A015951 (b=5), this sequence (b=6), A015954 (b=7), A015955 (b=8), A015957 (b=9), A015958 (b=10), A015960 (b=11), A015961 (b=12), A015963 (b=13), A015965 (b=14), A015968 (b=15), A015969 (b=16).
Column k=6 of A333429.
Sequence in context: A221962 A373684 A294292 * A206931 A188608 A188601
KEYWORD
nonn
STATUS
approved