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A100132 Sum C(n-2k,2k)2^(n-3k), k=0..floor(n/4). 2
1, 2, 4, 8, 18, 44, 112, 288, 740, 1896, 4848, 12384, 31624, 80752, 206208, 526592, 1344784, 3434272, 8770368, 22397568, 57198368, 146071744, 373034240, 952645120, 2432840256, 6212924032, 15866403584, 40519208448, 103476899968 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Binomial transform of 1,1,1,1,3,3,7,7,41,... (g.f. (1-x)(1+x)^2/(1-2x^2-x^4)).

LINKS

Table of n, a(n) for n=0..28.

Index entries for linear recurrences with constant coefficients, signature (4,-4,0,2)

FORMULA

G.f.: (1-2x)/((1-2x)^2-2x^4); a(n)=4a(n-1)-4a(n-2)+2a(n-3).

a(n)=sum{k=0..floor(n/2), C(n-k, k)2^(n-3k/2)(1+(-1)^k)/2} - Paul Barry, Jan 22 2005

MATHEMATICA

LinearRecurrence[{4, -4, 0, 2}, {1, 2, 4, 8}, 30] (* Harvey P. Dale, Jun 07 2016 *)

CROSSREFS

Cf. A100131, A100133.

Sequence in context: A193617 A233139 A114203 * A176720 A088457 A006786

Adjacent sequences:  A100129 A100130 A100131 * A100133 A100134 A100135

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Nov 06 2004

STATUS

approved

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Last modified October 17 19:36 EDT 2018. Contains 316293 sequences. (Running on oeis4.)