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A027407 Number of labeled servers of dimension 20. 1
1, 20, 590, 21680, 935770, 45961096, 2515881220, 151228367840, 9871829559980, 693789631115120, 52132594993215496, 4164523150393491520, 351983138874505854040, 31348448683850114451680 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

R. Donaghey, Binomial self-inverse sequences and tangent coefficients, J. Combin. Theory, Series A, 21 (1976), 155-163.

FORMULA

E.g.f.: exp( sum( ((1+x)^i-1)/i, i=1..20 ) ).

MATHEMATICA

Table[n!*SeriesCoefficient[E^(Sum[((1+x)^i - 1)/i, {i, 1, 20}]), {x, 0, n}], {n, 0, 20}] (* Vincenzo Librandi, Jan 01 2013 *)

CROSSREFS

Sequence in context: A012568 A259057 A184123 * A116218 A035279 A015268

Adjacent sequences:  A027404 A027405 A027406 * A027408 A027409 A027410

KEYWORD

nonn

AUTHOR

Olivier Gérard

STATUS

approved

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Last modified February 28 22:08 EST 2020. Contains 332335 sequences. (Running on oeis4.)