|
| |
|
|
A073075
|
|
Generating function satisfies A(x) = exp(2A(x)x + 2A(x^3)x^3/3 + 2A(x^5)x^5/5 + 2A(x^7)x^7/7 +...).
|
|
0
|
|
|
|
1, 2, 6, 22, 86, 358, 1554, 6950, 31822, 148434, 702802, 3369046, 16319050, 79749294, 392711090, 1946732854, 9706813790, 48651303118, 244972282734, 1238621756174, 6286144819506, 32011282859598, 163517409895602
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,2
|
|
|
LINKS
|
Table of n, a(n) for n=0..22.
|
|
|
FORMULA
|
G.f.: A(x) = exp(sum_{n=0..inf} 2A(x^(2n+1))*x^(2n+1)/(2n+1)), A(0)=1, where A(x) = 1 + 2x + 6x^2 + 22x^3 + 86x^4 + 358x^5 +...
|
|
|
MAPLE
|
spec := [S, {B=Set(S), C=PowerSet(S), S=Prod(Z, B, C)}, unlabeled]: seq(combstruct[count](spec, size=n), n=1..20); (Vladeta Jovovic, Feb 10 2005)
|
|
|
CROSSREFS
|
Sequence in context: A150256 A150257 A150258 * A153475 A150259 A165531
Adjacent sequences: A073072 A073073 A073074 * A073076 A073077 A073078
|
|
|
KEYWORD
|
easy,nonn,changed
|
|
|
AUTHOR
|
Paul D. Hanna, Aug 17 2002
|
|
|
STATUS
|
approved
|
| |
|
|
