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Search: id:A026585
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A026585 a(n)=T(n,n), T given by A026584. Also a(n) = number of integer strings s(0),...,s(n) counted by T, such that s(n)=0. +0
3
1, 0, 2, 2, 8, 14, 40, 86, 222, 518, 1296, 3130, 7770, 19066, 47324, 117094, 291260, 724302, 1806220, 4507230, 11266718, 28188070, 70609316, 177023466, 444231564, 1115639586, 2803975860, 7052132546, 17748069294, 44693162266 (list; graph; listen)
OFFSET

0,3

COMMENT

The signed sequence 1,0,2,-2,8,-14,... is the inverse binomial transform of A026569. - Paul Barry (pbarry(AT)wit.ie), Sep 09 2004

LINKS

J. W. Layman, The Hankel Transform and Some of its Properties, J. Integer Sequences, 4 (2001), #01.1.5.

FORMULA

G.f.: sqrt[(1-x)/(1-x-4x^2)]. - Ralf Stephan, Jan 08 2004

Contribution from Paul Barry (pbarry(AT)wit.ie), Jul 01 2009: (Start)

G.f.: 1/(1-2x^2/(1-x-x^2/(1-x^2/(1-x-x^2/(1-x^2/(1-x-x^2/(1-... (continued fraction);

a(0)=1, a(n)=sum{k=0..floor(n/2), (k/(n-k))C(n-k,k)*A000984(k)}. (End)

CROSSREFS

Sequence in context: A045686 A045677 A005633 this_sequence A098273 A052970 A109190

Adjacent sequences: A026582 A026583 A026584 this_sequence A026586 A026587 A026588

KEYWORD

nonn

AUTHOR

Clark Kimberling (ck6(AT)evansville.edu)

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Last modified December 5 20:25 EST 2009. Contains 170428 sequences.


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