|
Search: id:A003025
|
|
|
| A003025 |
|
Number of n-node labeled acyclic digraphs with 1 out-point.
(Formerly M2083)
|
|
+0
7
|
|
| 1, 2, 15, 316, 16885, 2174586, 654313415, 450179768312, 696979588034313, 2398044825254021110, 18151895792052235541515, 299782788128536523836784628, 10727139906233315197412684689421
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
REFERENCES
|
R. W. Robinson, Counting labeled acyclic digraphs, pp. 239-273 of F. Harary, editor, New Directions in the Theory of Graphs. Academic Press, NY, 1973.
|
|
EXAMPLE
|
a(2) = 2: o-->--o (2 ways)
a(3) = 15: o-->--o-->--o (6 ways) and
o ... o o-->--o
.\ . / . \ . /
. v v ... v v
.. o ..... o
(3 ways) (6 ways)
|
|
CROSSREFS
|
Cf. A058876, A003026.
Adjacent sequences: A003022 A003023 A003024 this_sequence A003026 A003027 A003028
Sequence in context: A076111 A087526 A059167 this_sequence A015200 A030642 A068391
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
njas
|
|
EXTENSIONS
|
More terms from Vladeta Jovovic (vladeta(AT)Eunet.yu), Apr 10 2001
|
|
|
Search completed in 0.002 seconds
|
