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A276969 Odd integers n such that 2^n == 2^7 (mod n). 7
1, 3, 7, 15, 49, 91, 133, 217, 255, 259, 301, 427, 469, 511, 527, 553, 679, 721, 763, 889, 973, 1015, 1057, 1099, 1141, 1267, 1351, 1393, 1477, 1561, 1603, 1687, 1897, 1939, 1981, 2107, 2149, 2191, 2317, 2359, 2443, 2569, 2611, 2653, 2779, 2863, 2947, 3031, 3073, 3199, 3241, 3409, 3493, 3661, 3787 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Also, integers n such that 2^(n-7) == 1 (mod n).

Contains A208155 as a subsequence.

For all m, 2^A015922(m)-1 belongs to this sequence.

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..10000

MATHEMATICA

m = 2^7; Join[Select[Range[1, m, 2], Divisible[2^# - m, #] &],

Select[Range[m + 1, 10^3, 2], PowerMod[2, #, #] == m &]] (* Robert Price, Oct 12 2018 *)

PROG

(PARI) is(n)=n%2 && Mod(2, n)^n==128 \\ Charles R Greathouse IV, Sep 22 2016

CROSSREFS

The odd terms of A015927.

Odd integers n such that 2^n == 2^k (mod n): A176997 (k=1), A173572 (k=2), A276967 (k=3), A033984 (k=4), A276968 (k=5), A215610 (k=6), this sequence (k=7), A215611 (k=8), A276970 (k=9), A215612 (k=10), A276971 (k=11), A215613 (k=12).

Cf. A015922, A208155.

Sequence in context: A097111 A151401 A080567 * A146448 A192169 A290470

Adjacent sequences:  A276966 A276967 A276968 * A276970 A276971 A276972

KEYWORD

nonn,easy

AUTHOR

Max Alekseyev, Sep 22 2016

STATUS

approved

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Last modified December 12 23:21 EST 2019. Contains 329963 sequences. (Running on oeis4.)