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A091825
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Integers of the form ((p-1)!*2^(p-1) + 1)/p.
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1
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2, 3, 77, 6583, 337808291, 150922350277, 80658585770586353, 88333886984966359579, 204973945587849174028466087, 2822166959135536313284193618131862069, 9187519016643816926988413546511855483871
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| If p is prime and gcd(q,p)=1 then p divide (p-1)!*q^(p-1) + 1
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EXAMPLE
| a(1) = ((1-1)!*2^(1-1) + 1)/1 = 2
((2-1)!*2^(2-1) + 1)/2 = 3/2 is not an integer
a(2) = ((3-1)!*2^(3-1) + 1)/3 = 3
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MATHEMATICA
| Select[Table[((n-1)! 2^(n-1)+1)/n, {n, 35}], IntegerQ] (* From Harvey P. Dale, Mar 24 2011 *)
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PROG
| (PARI) for (i=1, 100, if(denominator(((i-1)!*2^(i-1)+1)/i)==1, print((((i-1)!*2^(i-1)+1)/i)));
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CROSSREFS
| Cf. A091824.
Sequence in context: A140546 A042233 A176290 * A166091 A068185 A037391
Adjacent sequences: A091822 A091823 A091824 * A091826 A091827 A091828
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KEYWORD
| nonn
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AUTHOR
| Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Mar 09 2004
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EXTENSIONS
| Additional term provided by Harvey P. Dale, Mar 24 2011.
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