|
| |
|
|
A053525
|
|
E.g.f.: (1-x)/(2-exp(x)).
|
|
3
| |
|
|
1, 0, 1, 4, 23, 166, 1437, 14512, 167491, 2174746, 31374953, 497909380, 8619976719, 161667969646, 3265326093109, 70663046421208, 1631123626335707, 40004637435452866, 1038860856732399105, 28476428717448349996, 821656049857815980455
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,4
|
|
|
REFERENCES
| Guruswami, Venkatesan, Enumerative aspects of certain subclasses of perfect graphs. Discrete Math. 205 (1999), 97-117. See Th. 6.3.
R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Problem 5.4(a).
|
|
|
LINKS
| T. D. Noe, Table of n, a(n) for n=0..100
|
|
|
CROSSREFS
| a(n)=c(n)-n*c(n-1) where c() = A000670.
Cf. A005840.
Sequence in context: A182969 A111547 A158884 * A113869 A084357 A075729
Adjacent sequences: A053522 A053523 A053524 * A053526 A053527 A053528
|
|
|
KEYWORD
| nonn,nice,easy
|
|
|
AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Jan 15 2000
|
| |
|
|
