|
| |
|
|
A060516
|
|
Number of series-reduced (or homeomorphically irreducible) graphs with loops on n labeled nodes.
|
|
12
|
|
|
|
1, 1, 5, 26, 328, 9700, 711836, 111817032, 35130791054, 21495893690664, 25409892375220474, 58052821046020873856, 257486314335782707924088, 2230295461268044025586193298, 37948847404292424846290915818844
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,3
|
|
|
REFERENCES
|
I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, John Wiley and Sons, N.Y., 1983.
|
|
|
LINKS
|
Table of n, a(n) for n=0..14.
|
|
|
FORMULA
|
E.g.f. : (1 + x)^( - 1/2) * exp( - x/2 - x^2/4) * Sum_{k=0..inf} 2^binomial(k + 1, 2) * exp( - x * k^2/(2 * (1 + x)) + x * k/2) * x^k/k!.
|
|
|
CROSSREFS
|
Cf. A003514. Row sums of A060517.
Sequence in context: A203198 A197784 A106296 * A077537 A140423 A090644
Adjacent sequences: A060513 A060514 A060515 * A060517 A060518 A060519
|
|
|
KEYWORD
|
easy,nonn,changed
|
|
|
AUTHOR
|
Vladeta Jovovic, Mar 24 2001
|
|
|
STATUS
|
approved
|
| |
|
|
