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A296243
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Numbers k such that the multiplicative order of 2 modulo k is even.
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4
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3, 5, 9, 11, 13, 15, 17, 19, 21, 25, 27, 29, 33, 35, 37, 39, 41, 43, 45, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 75, 77, 81, 83, 85, 87, 91, 93, 95, 97, 99, 101, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 153
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OFFSET
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1,1
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COMMENTS
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LINKS
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MATHEMATICA
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A036259 = Select[Range[1, 199, 2], OddQ[MultiplicativeOrder[2, #]] &];
Select[Range[1, 153, 2], EvenQ[MultiplicativeOrder[2, #]] &] (* Amiram Eldar, Jul 30 2020 *)
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PROG
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(PARI) { is_A296243(n) = (n%2) && !(znorder(Mod(2, n))%2); }
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CROSSREFS
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The prime terms are given by A014662.
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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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