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A069152
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a(n) = (n-1)!-n^tau(n)/n^2.
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0
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0, 1, 2, 23, 84, 719, 4976, 40311, 362780, 3628799, 39896064, 479001599, 6227020604, 87178290975, 1307674363904, 20922789887999, 355687427991024, 6402373705727999, 121645100408672000, 2432902008176639559
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OFFSET
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2,3
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COMMENTS
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n and a(n) have the same parity.
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LINKS
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MATHEMATICA
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Table[(n - 1)! - n^DivisorSigma[0, n]/n^2, {n, 2, 25}] (* Wesley Ivan Hurt, Jan 20 2024 *)
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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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