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A342974
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Primes p such that the order of 2 modulo p is not divisible by the largest odd divisor of p - 1.
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0
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31, 43, 109, 127, 151, 157, 223, 229, 241, 251, 277, 283, 307, 331, 397, 431, 433, 439, 457, 499, 571, 601, 631, 641, 643, 673, 683, 691, 727, 733, 739, 811, 911, 919, 953, 971, 997, 1013, 1021, 1051, 1069, 1093, 1103, 1163, 1181, 1321, 1327, 1399, 1423, 1429
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OFFSET
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1,1
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COMMENTS
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Every prime factor of a composite Fermat number belongs to this sequence.
If a prime of the form 3*2^k + 1 belongs to this sequence, then k is in A204620 (see Golomb).
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LINKS
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MATHEMATICA
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Select[Prime@Range@300, Mod[MultiplicativeOrder[2, #], Max@Select[Divisors[#-1], OddQ]]!=0&] (* Giorgos Kalogeropoulos, Apr 02 2021 *)
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PROG
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(PARI) forprime(p=3, 1429, if(Mod(znorder(Mod(2, p)), (p-1)>>valuation(p-1, 2)), print1(p, ", ")));
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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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