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A068483
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Numbers n such that gcd(n!-1,2^n-1)>1.
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5
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11, 15, 35, 75, 83, 111, 119, 135, 155, 179, 219, 231, 243, 323, 359, 375, 455, 459, 483, 491, 515, 519, 525, 531, 551, 611, 615, 639, 651, 663, 699, 719, 723, 735, 771, 779, 783, 803, 879, 915, 923, 939, 999, 1043, 1103, 1119, 1175, 1199, 1271, 1323
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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Select[Range[2500], GCD[#! - 1, 2^# - 1] > 1 &] (* G. C. Greubel, Oct 15 2018 *)
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PROG
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(PARI) isok(n) = gcd(n!-1, 2^n-1) > 1; \\ Michel Marcus, Oct 16 2018
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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