A110377 - OEIS

A110377

a(n) = Sum_{r < n, gcd(r,n)=1} n!/r!.

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

1,2

LINKS

Table of n, a(n) for n=1..20.

EXAMPLE

a(6) = 6!(1/1! + 1/5!) = 726.

MAPLE

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

CROSSREFS

Cf. A038048, A110276, A110373, A110374.

Sequence in context: A138912 A374827 A002747 * A338436 A041877 A090208

Adjacent sequences: A110374 A110375 A110376 * A110378 A110379 A110380

KEYWORD

easy,nonn

AUTHOR

Amarnath Murthy, Jul 24 2005

EXTENSIONS

More terms from Emeric Deutsch, Jul 25 2005

STATUS

approved