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 A243805 Integers k such that 6 is a 6th power mod k. 2
 1, 2, 3, 5, 6, 10, 15, 23, 25, 29, 30, 46, 47, 50, 53, 58, 69, 71, 75, 87, 94, 101, 106, 115, 125, 138, 139, 141, 142, 145, 149, 150, 159, 163, 167, 173, 174, 191, 197, 202, 213, 230, 235, 239, 241, 250, 263, 265, 269, 278, 282, 290, 293, 298, 303, 307, 311, 313, 317, 318, 326, 334, 337, 345, 346, 355, 359, 375, 379, 382, 383, 389 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS All n such that there exists at least one integer x with x^6 == 6 mod n. n is in the sequence iff n is not divisible by 4 or 9 or any member of A243768. LINKS Robert Israel, Table of n, a(n) for n = 1..10000 EXAMPLE 5 is in the sequence because 1^6 == 6 mod 5. MAPLE select(n -> nops([msolve(x^6-6, n)])>0, [\$1..1000]); MATHEMATICA Select[Range[1000], # == 1 || Solve[x^6-6 == 0, x, Modulus -> #] != {}&] (* Jean-François Alcover, Apr 27 2019 *) PROG (PARI) isok(n) = ispower(Mod(6, n), 6) ; \\ fails with 2.11.1 but will work with 2.11.2; Michel Marcus, Apr 28 2019 CROSSREFS Cf. A243768 (primes not in this sequence). Sequence in context: A262931 A018524 A057035 * A018594 A018626 A018305 Adjacent sequences:  A243802 A243803 A243804 * A243806 A243807 A243808 KEYWORD nonn AUTHOR Robert Israel, Jun 10 2014 STATUS approved

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Last modified April 7 15:56 EDT 2020. Contains 333306 sequences. (Running on oeis4.)