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A147841
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a(n)=11*a(n-1)-9*a(n-2), a(0)=1, a(1)=9 .
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2
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1, 9, 90, 909, 9189, 92898, 939177, 9494865, 95990922, 970446357, 9810991629, 99186890706, 1002756873105, 10137643587801, 102489267607866, 1036143151396317, 10475171256888693, 105901595463208770
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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FORMULA
| a(n)=Sum_{k, 0<=k<=n}A147703(n,k)*8^k . G.f.: (1-2x)/(1-11x+9*x^2).
a(n)=(1/2)*[(11/2)-(1/2)*sqrt(85)]^n-(7/170)*[(11/2)-(1/2)*sqrt(85)]^n*sqrt(85)+(7/170)*sqrt(85) *[(11/2)+(1/2)*sqrt(85)]^n+(1/2)*[(11/2)+(1/2)*sqrt(85)]^n, with n>=0 [From Paolo P. Lava (paoloplava(AT)gmail.com), Nov 18 2008]
a(n)= ((85-7*sqrt(85))/170)*(5.5-0.5*sqrt(85))^n+((85+7*sqrt(85))/170)*(5.5+0.5*sqrt(85))^n [From Richard Choulet (richardchoulet(AT)yahoo.fr), Nov 19 2008]
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CROSSREFS
| Sequence in context: A173480 A052268 A155199 * A036258 A098399 A143079
Adjacent sequences: A147838 A147839 A147840 * A147842 A147843 A147844
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KEYWORD
| nonn
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AUTHOR
| Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 14 2008
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EXTENSIONS
| Corrected entries. - Paolo P. Lava (paoloplava(AT)gmail.com), Nov 18 2008
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