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A336655
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Odd numbers k such that the multiplicative order of 2 modulo k is squarefree.
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3
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1, 3, 7, 9, 11, 21, 23, 31, 33, 43, 47, 49, 59, 63, 67, 69, 71, 77, 79, 83, 89, 93, 99, 103, 107, 121, 127, 129, 131, 139, 141, 147, 151, 161, 167, 177, 179, 191, 201, 207, 211, 213, 217, 223, 227, 231, 233, 237, 239, 249, 253, 263, 267, 279, 281, 283, 301, 307
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OFFSET
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1,2
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LINKS
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FORMULA
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The number of terms not exceeding x is (a + o(1))* x * log(x)^(b-1), where a and b (~ 0.46437) are constants (Pappalardi, 2003).
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EXAMPLE
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3 is a term since the multiplicative order of 2 modulo 3 is 2 which is squarefree.
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MATHEMATICA
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Select[2 * Range[160] - 1, SquareFreeQ[MultiplicativeOrder[2, #]] &]
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PROG
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(PARI) isok(k) = (k % 2) && issquarefree(znorder(Mod(2, k))); \\ Michel Marcus, Jul 29 2020
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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