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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

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Last modified July 25 16:19 EDT 2014. Contains 244915 sequences.