login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A112328 a(n)=(n+1)binomial(2n+2,n+1)-3*4^n+binomial(2n,n). 1
2, 18, 108, 562, 2724, 12660, 57240, 253842, 1109748, 4798780, 20572392, 87580308, 370706408, 1561573032, 6551178288, 27387484242, 114146434068, 474476717292, 1967642119368, 8142727008732, 33634295542968, 138696447565272 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row sums of A112327.

REFERENCES

F. Ruskey, Average shape of binary trees, SIAM J. Alg. Disc. Meth., 1, 1980, 43-50 (Eq. (8)).

LINKS

Table of n, a(n) for n=1..22.

FORMULA

G.f.=4z[2-sqrt(1-4z)]/[(1-4z)^(3/2)(1+sqrt(1-4z)]

MAPLE

a:=n->(n+1)*binomial(2*n+2, n+1)-3*4^n+binomial(2*n, n): seq(a(n), n=1..25);

CROSSREFS

Cf. A112327.

Sequence in context: A094251 A101570 A006043 * A038721 A064837 A224902

Adjacent sequences:  A112325 A112326 A112327 * A112329 A112330 A112331

KEYWORD

nonn

AUTHOR

Emeric Deutsch, Sep 04 2005

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified November 29 01:24 EST 2014. Contains 250479 sequences.