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A155144
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a(n)=9*a(n-1)+9*a(n-2), n>2 ; a(0)=1, a(1)=8, a(2)=80 .
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0
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1, 8, 80, 792, 7848, 77760, 770472, 7634088, 75641040, 749476152, 7426054728, 73579777920, 729052493832, 7223690445768, 71574686456400, 709185392119512, 7026840707183208, 69624234893724480, 689859680408169192
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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FORMULA
| G.f.: (1-x-x^2)/(1-9*x-9*x^2).
a(n)=4*{[(9/2)+(3/2)*sqrt(13)]^(n-1)+[(9/2)-(3/2)*sqrt(13)]^(n-1)}+(44/39)*sqrt(13)*{[(9/2)+(3/2)*sqrt(13)]^(n-1)-[(9/2)-(3/2)*sqrt(13)]^(n-1)}+(1/9)*[C(2*n,n) mod 2], with n>=0 [From Paolo P. Lava (paoloplava(AT)gmail.com), Jan 26 2009]
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MATHEMATICA
| Join[{1}, LinearRecurrence[{9, 9}, {8, 80}, 20]] (* or *) CoefficientList[ Series[ (1-x-x^2)/(1-9x-9x^2), {x, 0, 20}], x] (* From Harvey P. Dale, June 19 2011 *)
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CROSSREFS
| Sequence in context: A145729 A182604 A024101 * A136949 A102592 A053175
Adjacent sequences: A155141 A155142 A155143 * A155145 A155146 A155147
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KEYWORD
| nonn
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AUTHOR
| Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jan 21 2009
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