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A027408
Number of labeled servers of dimension 21.
1
1, 21, 651, 25151, 1141791, 58999227, 3398446177, 215000489757, 14773746912897, 1093126139653877, 86488314164428659, 7275617735214635079, 647633785826931486079, 60753264284081214177339
OFFSET
0,2
LINKS
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..21 ) ).
MATHEMATICA
Table[n!*SeriesCoefficient[E^(Sum[((1+x)^i - 1)/i, {i, 1, 21}]), {x, 0, n}], {n, 0, 20}] (* Vincenzo Librandi, Jan 01 2013 *)
CROSSREFS
Sequence in context: A163032 A209264 A012501 * A177840 A297312 A158216
KEYWORD
nonn
STATUS
approved