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 A015922 Numbers k such that 2^k == 8 (mod k). 20
 1, 2, 3, 4, 8, 9, 15, 21, 33, 39, 51, 57, 63, 69, 87, 93, 111, 123, 129, 141, 159, 177, 183, 195, 201, 213, 219, 237, 248, 249, 267, 291, 303, 309, 315, 321, 327, 339, 381, 393, 399, 411, 417, 447, 453, 471, 489, 501, 519, 537, 543, 573, 579, 591, 597, 633 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS For all m, 2^A015921(m) - 1 belongs to this sequence. LINKS Michael De Vlieger, Table of n, a(n) for n = 1..29055 (first 6822 terms from Zak Seidov) OEIS Wiki, 2^n mod n. MATHEMATICA a015922Q[n_Integer] := If[Mod[2^n, n] == Mod[8, n], True, False]; a015922[n_Integer] := Flatten[Position[Thread[a015922Q[Range[n]]], True]]; a015922[1000000] (* Michael De Vlieger, Jul 16 2014 *) m = 8; Join[Select[Range[m], Divisible[2^# - m, #] &], Select[Range[m + 1, 10^3], PowerMod[2, #, #] == m &]] (* Robert Price, Oct 12 2018 *) Join[{1, 2, 3, 4, 8}, Select[Range[650], PowerMod[2, #, #]==8&]] (* Harvey P. Dale, Aug 22 2020 *) PROG (PARI) isok(n) = Mod(2, n)^n == Mod(8, n); \\ Michel Marcus, Oct 13 2013, Jul 16 2014 CROSSREFS Contains A033553 as a subsequence. The odd terms form A276967. Cf. A015921, A130133, A130134. Sequence in context: A281089 A242333 A231811 * A373725 A212255 A078829 Adjacent sequences: A015919 A015920 A015921 * A015923 A015924 A015925 KEYWORD nonn AUTHOR Robert G. Wilson v EXTENSIONS First 5 terms inserted by David W. Wilson STATUS approved

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Last modified September 8 09:46 EDT 2024. Contains 375753 sequences. (Running on oeis4.)