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A112328
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a(n)=(n+1)binomial(2n+2,n+1)-3*4^n+binomial(2n,n).
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1
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2, 18, 108, 562, 2724, 12660, 57240, 253842, 1109748, 4798780, 20572392, 87580308, 370706408, 1561573032, 6551178288, 27387484242, 114146434068, 474476717292, 1967642119368, 8142727008732, 33634295542968, 138696447565272
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OFFSET
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1,1
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COMMENTS
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Row sums of A112327.
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REFERENCES
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F. Ruskey, Average shape of binary trees, SIAM J. Alg. Disc. Meth., 1, 1980, 43-50 (Eq. (8)).
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LINKS
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Table of n, a(n) for n=1..22.
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FORMULA
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G.f.=4z[2-sqrt(1-4z)]/[(1-4z)^(3/2)(1+sqrt(1-4z)]
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MAPLE
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a:=n->(n+1)*binomial(2*n+2, n+1)-3*4^n+binomial(2*n, n): seq(a(n), n=1..25);
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CROSSREFS
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Cf. A112327.
Sequence in context: A094251 A101570 A006043 * A038721 A064837 A027433
Adjacent sequences: A112325 A112326 A112327 * A112329 A112330 A112331
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KEYWORD
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nonn
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AUTHOR
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Emeric Deutsch, Sep 04 2005
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STATUS
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approved
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