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A089043
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n!^2+(-1)^n : p = 2*n+1 is prime iff it divides a(n).
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0
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0, 5, 35, 577, 14399, 518401, 25401599, 1625702401, 131681894399, 13168189440001, 1593350922239999, 229442532802560001, 38775788043632639999, 7600054456551997440001
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| p = 2*n+1 is prime iff it divides a(n) (wilson's theorem) for instance let n=5, p =11 : a(5) = 14399 = 11*1309, so 11 is prime
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FORMULA
| a(n) = n^2*(a(n-1)-(-1)^(n-1))+(-1)^n; generating function = n!^2+(-1)^n
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EXAMPLE
| a(5) = 14399 because 14399=(5!)^2+(-1)^5
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CROSSREFS
| Sequence in context: A034217 A011556 A194927 * A034236 A058015 A053420
Adjacent sequences: A089040 A089041 A089042 * A089044 A089045 A089046
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KEYWORD
| easy,nonn
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AUTHOR
| Serge Boisse (serge.boisse(AT)aviation-civile.gouv.fr), Dec 02 2003
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