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A066160
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Numbers n such that 4n-1 divides (2n-1)! - 1.
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2
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1, 6, 8, 15, 18, 21, 27, 35, 38, 42, 53, 56, 60, 63, 68, 71, 77, 78, 83, 90, 95, 110, 116, 117, 122, 125, 137, 147, 161, 162, 165, 180, 188, 203, 207, 215, 221, 227, 228, 230, 242, 243, 246, 258, 260, 266, 276, 291, 293, 306, 308, 315, 320, 321
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OFFSET
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1,2
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LINKS
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MAPLE
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MATHEMATICA
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Select[Range[350], Mod[(2 # - 1)! - 1, 4 # - 1] == 0 &] (* Vincenzo Librandi, Dec 02 2015 *)
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PROG
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(PARI) { n=0; for (m=1, 10^9, if (frac(((2*m - 1)! - 1)/(4*m - 1)) == 0, write("b066160.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Feb 03 2010
(Magma) [n: n in [1..350] | (Factorial(2*n-1)-1) mod(4*n-1) eq 0]; // Vincenzo Librandi, Dec 02 2015
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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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