|
Search: id:A005387
|
|
|
| A005387 |
|
Number of partitional matroids on n elements.
(Formerly M1493)
|
|
+0
1
|
|
| 1, 2, 5, 16, 62, 276, 1377, 7596, 45789, 298626, 2090910, 15621640, 123897413, 1038535174, 9165475893, 84886111212, 822648571314, 8321077557124, 87648445601429, 959450073912136, 10894692556576613, 128114221270929646
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
REFERENCES
|
Recski, A.; Enumerating partitional matroids. Stud. Sci. Math. Hungar. 9 (1974), 247-249 (1975).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
|
|
LINKS
|
T. D. Noe, Table of n, a(n) for n=0..100
Index entries for sequences related to matroids
|
|
FORMULA
|
E.g.f.: exp ((x-1)*e^x + 2*x + 1 ).
|
|
CROSSREFS
|
Sequence in context: A033543 A124531 A129578 this_sequence A138549 A144188 A157314
Adjacent sequences: A005384 A005385 A005386 this_sequence A005388 A005389 A005390
|
|
KEYWORD
|
nonn,easy,nice
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com).
|
|
EXTENSIONS
|
More terms from James A. Sellers (sellersj(AT)math.psu.edu), Aug 21 2000
|
|
|
Search completed in 0.002 seconds
|
