login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A112805 Expansion of solution of functional equation. 0
1, 1, 1, 1, 1, 2, 5, 11, 21, 37, 66, 127, 261, 545, 1119, 2255, 4529, 9202, 18989, 39566, 82614, 172272, 359159, 750699, 1575649, 3319942, 7012833, 14834345, 31414423, 66619692, 141526459, 301202699, 642055773, 1370429491, 2928418794 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..35.

FORMULA

G.f. A(x)=y satisfies y=x+(xy)/(1-(xy)^2).

Series reversion of g.f. A(x) is -A(-x).

PROG

(PARI) {a(n)=local(A); if(n<1, 0, A=x+O(x^2); for(k=1, n, A=x+subst(x/(1-x^2), x, x*A)); polcoeff(A, n))}

CROSSREFS

Sequence in context: A103198 A183929 A003522 * A119970 A326509 A082775

Adjacent sequences:  A112802 A112803 A112804 * A112806 A112807 A112808

KEYWORD

nonn

AUTHOR

Michael Somos, Sep 20 2005

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 22 16:06 EDT 2021. Contains 343177 sequences. (Running on oeis4.)