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A027408 Number of labeled servers of dimension 21. 0
1, 21, 651, 25151, 1141791, 58999227, 3398446177, 215000489757, 14773746912897, 1093126139653877, 86488314164428659, 7275617735214635079, 647633785826931486079, 60753264284081214177339 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

REFERENCES

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} ] ]

CROSSREFS

Sequence in context: A025752 A163032 A012501 * A177840 A158216 A020246

Adjacent sequences:  A027405 A027406 A027407 * A027409 A027410 A027411

KEYWORD

nonn

AUTHOR

Olivier Gerard (olivier.gerard(AT)gmail.com)

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Last modified February 14 23:53 EST 2012. Contains 205689 sequences.