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A084132
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a(n)=4a(n-1)+6a(n-2), a(0)=1,a(1)=2.
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3
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1, 2, 14, 68, 356, 1832, 9464, 48848, 252176, 1301792, 6720224, 34691648, 179087936, 924501632, 4772534144, 24637146368, 127183790336, 656558039552, 3389334900224, 17496687838208, 90322760754176, 466271170045952
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Binomial transform of A002535.
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FORMULA
| a(n)=(2+sqrt(10))^n/2+(2-sqrt(10))^n/2; G.f.: (1-2x)/(1-4x-6x^2); E.g.f. : exp(2x)cosh(sqrt(10)x).
a(n) = Sum_{k, 0<=k<=n} A201730(n,k)*9^k . - DELEHAM Philippe, Dec 06 2011
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PROG
| (Other) sage: [lucas_number2(n, 4, -6)/2 for n in xrange(0, 22)]# [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 14 2009]
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CROSSREFS
| Cf. A005667.
Sequence in context: A109869 A197777 A197608 * A084770 A086243 A206947
Adjacent sequences: A084129 A084130 A084131 * A084133 A084134 A084135
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), May 16 2003
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