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A056819
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a(n) = Product_{k|n} (n+1-k).
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2
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1, 2, 3, 12, 5, 120, 7, 280, 63, 540, 11, 83160, 13, 1456, 2145, 28080, 17, 636480, 19, 1136960, 5985, 5544, 23, 1070845776, 525, 9100, 12825, 6237000, 29, 5320224000, 31, 12226400, 23529, 20196, 31465, 582876756000, 37, 28120, 38961, 44639955360
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OFFSET
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1,2
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LINKS
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FORMULA
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EXAMPLE
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a(6) = (6+1-1) *(6+1-2) *(6+1-3) *(6+1-6) = 6 *5 *4 *1 = 120, since the positive divisors of 6 are 1, 2, 3, 6.
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MATHEMATICA
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PROG
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(PARI) a(n) = my(d=divisors(n)); prod(k=1, #d, n+1-d[k]); \\ Michel Marcus, Sep 30 2016
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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