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A237580
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a(n) = (2n)! - n! + 1.
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3
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1, 2, 23, 715, 40297, 3628681, 479000881, 87178286161, 20922789847681, 6402373705365121, 2432902008173011201, 1124000727777567763201, 620448401733238960358401, 403291461126605629356979201, 304888344611713860414325708801, 265252859812191058635000805632001
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OFFSET
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0,2
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COMMENTS
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Primes are listed in A118812, the corresponding indices in A237443; the least prime factor of a(n) in A237579.
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LINKS
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MATHEMATICA
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PROG
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(Magma) [Factorial(2*n)-Factorial(n)+1: n in [0..15]]; // Vincenzo Librandi, Feb 11 2014
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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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