A015931 Positive integers n such that 2^n (mod n) == 2^9 (mod n).

1, 2, 3, 4, 5, 8, 9, 16, 17, 21, 27, 32, 45, 63, 64, 99, 105, 117, 124, 128, 153, 171, 189, 207, 254, 256, 261, 273, 279, 333, 369, 387, 423, 429, 477, 512, 513, 531, 549, 585, 603, 639, 657, 711, 747, 801, 873, 909, 927, 945, 963, 981, 1017, 1143, 1179, 1197, 1209, 1233, 1251, 1341, 1359, 1365, 1413, 1467, 1472, 1503, 1504, 1557, 1611, 1629, 1665, 1719, 1737, 1773, 1785, 1791, 1899, 1971

Offset: 1

Author

Robert G. Wilson v

Keywords

• nonn

Comments

For all m, 2^A128123(m)-1 belongs to this sequence.

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..10000
• OEIS Wiki, 2^n mod n

Crossrefs

Contains A208157 as a subsequence.

The odd terms form A276970.

Programs

Mathematica

Select[Range[2000],PowerMod[2,9,#]==PowerMod[2,#,#]&] (* Harvey P. Dale, Apr 01 2017 *)

PARI

isok(n) = Mod(2, n)^n == 2^9; \\ Michel Marcus, Sep 23 2016

Extensions

Edited by Max Alekseyev, Jul 30 2011

Definition clarified by Harvey P. Dale, Apr 01 2017