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A100132
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Sum C(n-2k,2k)2^(n-3k), k=0..floor(n/4).
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2
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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; internal format)
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OFFSET
| 0,2
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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)).
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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 (pbarry(AT)wit.ie), Jan 22 2005
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CROSSREFS
| Cf. A100131, A100133.
Sequence in context: A059221 A193617 A114203 * A176720 A088457 A006786
Adjacent sequences: A100129 A100130 A100131 * A100133 A100134 A100135
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Nov 06 2004
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