A276969 - OEIS

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A276969

Odd integers n such that 2^n == 2^7 (mod n).

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

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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: A371914 A151401 A080567 * A146448 A192169 A290470

Adjacent sequences: A276966 A276967 A276968 * A276970 A276971 A276972

KEYWORD

nonn,easy

AUTHOR

Max Alekseyev, Sep 22 2016

STATUS

approved