A128124 Numbers k such that 2^k == 12 (mod k).

1, 2, 4, 5, 3763, 125714, 167716, 1803962, 2895548, 4031785, 36226466, 16207566916, 103742264732, 29000474325364, 51053256144532, 219291270961199, 1611547934753332, 5816826177630619

Offset: 1

Author

Alexander Adamchuk, Feb 15 2007

Keywords

• hard
• more
• nonn

Links

• Joe K. Crump, 2^n mod n
• OEIS Wiki, 2^n mod n

Crossrefs

Cf. A015910, A036236, A050259, A033981, A051447, A033982, A051446, A033983, A128121, A128122, A128123, A128125, A128126.

Programs

Mathematica

m = 12; Join[Select[Range[m], Divisible[2^# - m, #] &],
Select[Range[m + 1, 10^6], PowerMod[2, #, #] == m &]] (* Robert Price, Oct 08 2018 *)

Extensions

More terms from Ryan Propper, Mar 23 2007

1, 2, 4 and 5 added by N. J. A. Sloane, Apr 23 2007

a(13)-a(15) from Max Alekseyev, May 19 2011

a(15) corrected, a(16)-a(18) added by Max Alekseyev, Oct 02 2016