|
|
A105205
|
|
G.f.: Sum((1-x)^(2*l)*Sum(x^((2*l-1)*k)/(1-2*x+x^k)^(2*l),k=1..infinity),l=1..infinity).
|
|
0
|
|
|
1, 1, 4, 6, 13, 24, 51, 101, 205, 407, 814, 1624, 3248, 6490, 12979, 25950, 51898, 103798, 207619, 415288, 830690, 1661590, 3323566, 6647779, 13296602, 26594769, 53191708, 106386020, 212774300, 425548246, 851088094, 1702147791, 3404222451
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,3
|
|
LINKS
|
|
|
FORMULA
|
Number of compositions of n such that the greatest part occurs with odd multiplicity.
|
|
EXAMPLE
|
a(4)=6 because we have (4),(3,1),(1,3),(2,1,1),(1,2,1) and (1,1,2).
|
|
MAPLE
|
G:=sum((1-x)^(2*l)*sum(x^((2*l-1)*k)/(1-2*x+x^k)^(2*l), k=1..30), l=1..20): Gser:=series(G, x=0, 35): seq(coeff(Gser, x^n), n=1..33); # Emeric Deutsch, Jun 07 2005
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|