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 A015921 Positive integers n such that 2^n == 4 (mod n). 16
 1, 2, 4, 6, 10, 12, 14, 22, 26, 30, 34, 38, 46, 58, 62, 74, 82, 86, 94, 106, 118, 122, 132, 134, 142, 146, 158, 166, 170, 178, 182, 194, 202, 206, 214, 218, 226, 254, 262, 274, 278, 298, 302, 314, 326, 334, 346, 358, 362, 372, 382, 386, 394, 398, 422, 446 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Odd terms are given by A173572. For all m, 2^A050259(m)-1 belongs to this sequence. LINKS T. D. Noe, Table of n, a(n) for n = 1..1000 OEIS Wiki, 2^n mod n MATHEMATICA Select[Range[500], PowerMod[2, #, #] == 4 &] (* Alonso del Arte, Jul 07 2011 *) CROSSREFS Contains A050990 as a subsequence. Cf. A015910, A173572. Sequence in context: A301646 A024892 A087136 * A232964 A132631 A248614 Adjacent sequences:  A015918 A015919 A015920 * A015922 A015923 A015924 KEYWORD nonn AUTHOR EXTENSIONS Edited and terms 1,2,4 prepended by Max Alekseyev, Jul 29 2011 STATUS approved

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Last modified February 24 01:11 EST 2020. Contains 332195 sequences. (Running on oeis4.)