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A132958 a(n) = n!*Sum_{d|n} (-1)^(d+1)/d!. 10
1, 1, 7, 11, 121, 479, 5041, 18479, 423361, 1844639, 39916801, 298710719, 6227020801, 43606442879, 1536517382401, 9589093113599, 355687428096001, 4259374594675199, 121645100408832001, 1135353600039859199 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..445

FORMULA

E.g.f.: Sum_{k>0} (-x)^k/(k!*(x^k-1)) or Sum_{k>0}(1-exp(-x^k)).

MATHEMATICA

f[n_] := Block[{d = Divisors@n}, Plus @@ (n!*(-1)^(d + 1)/d!)]; Array[f, 19] (* or *) (* Robert G. Wilson v, Sep 13 2007 *)

Rest[ Range[0, 20]! CoefficientList[ Series[ Sum[(-x)^k/(k!*(x^k - 1)), {k, 25}], {x, 0, 20}], x]] (* or *) (* Robert G. Wilson v, Sep 13 2007 *)

Rest[ Range[0, 20]! CoefficientList[ Series[ Sum[1 - Exp[ -x^k], {k, 25}], {x, 0, 20}], x]] (* Robert G. Wilson v, Sep 13 2007 *)

PROG

(PARI) a(n) = n!*sumdiv(n, d, (-1)^(d+1)/d!); \\ Michel Marcus, Sep 29 2017

CROSSREFS

Cf. A057625, A132959, A132960, A132961, A132962, A132963.

Sequence in context: A123763 A018680 A107187 * A241189 A057737 A130704

Adjacent sequences:  A132955 A132956 A132957 * A132959 A132960 A132961

KEYWORD

easy,nonn

AUTHOR

Vladeta Jovovic, Sep 06 2007

EXTENSIONS

More terms from Robert G. Wilson v, Sep 13 2007

STATUS

approved

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Last modified January 21 13:54 EST 2020. Contains 331113 sequences. (Running on oeis4.)