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A128123
Numbers k such that 2^k == 10 (mod k).
11
1, 2, 6, 18, 16666, 262134, 4048124214, 24430928839, 243293052886, 41293676570106, 3935632929857549
OFFSET
1,2
COMMENTS
Some larger terms: 266895924489780149, 2335291686841914329, 18494453435532853111
MATHEMATICA
m = 10; Join[Select[Range[m], Divisible[2^# - m, #] &],
Select[Range[m + 1, 10^6], PowerMod[2, #, #] == m &]] (* Robert Price, Oct 08 2018 *)
CROSSREFS
Cf. A015910, A036236, A050259 (numbers k such that 2^k == 3 (mod k)), A033981, A051447, A033982, A051446, A033983, A128121, A128122, A128124, A128125, A128126.
Sequence in context: A240643 A262971 A253380 * A227884 A186769 A213400
KEYWORD
hard,more,nonn
AUTHOR
Alexander Adamchuk, Feb 15 2007
EXTENSIONS
1, 2 and 6 added by N. J. A. Sloane, Apr 23 2007
Missing terms a(9)-a(10) added by Max Alekseyev, Dec 16 2013
a(11) from Max Alekseyev, Sep 27 2016
STATUS
approved