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A110377
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a(n) = Sum_{r < n, gcd(r,n)=1} n!/r!.
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2
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1, 2, 9, 28, 205, 726, 8659, 47384, 562545, 4234330, 68588311, 483088332, 10699776685, 102434734598, 2016289908585, 24588487650736, 611171244308689, 6456997293606738, 209020565553571999, 2838875160624256460
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OFFSET
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1,2
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LINKS
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EXAMPLE
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a(6) = 6!(1/1! + 1/5!) = 726.
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MAPLE
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a:=proc(n) local s, r: s:=0: for r from 1 to n do if gcd(r, n)=1 then s:=s+1/r! else s:=s: fi: od: n!*s end: seq(a(n), n=1..23); # Emeric Deutsch, Jul 25 2005
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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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EXTENSIONS
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STATUS
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approved
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