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Search: id:A152106
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| A152106 |
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((9+sqrt4)^n+(9-sqrt4)^n)/2 |
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+0
2
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| 1, 9, 85, 837, 8521, 88929, 944605, 10155357, 110061841, 1199150649, 13109949925, 143644498677, 1576134831961, 17309800577169, 190214028328045, 2090997865462797, 22991481397070881, 252839829506640489
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OFFSET
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0,2
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COMMENT
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a(n) = (11^n+7^n)/2. [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 26 2008]
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FORMULA
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a(n)=18*a(n-1)-77*a(n-2), n>1 ; a(0)=1, a(1)=9 . G.f.: (1-9*x)/(1-18*x+77*x^2). a(n)=(Sum_{k, 0<=k<=n}A098158(n,k)*9^(2*k)*4^(n-k))/9^n. [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 26 2008]
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EXAMPLE
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a(3)=837
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CROSSREFS
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Sequence in context: A163308 A160112 A108427 this_sequence A142982 A029711 A015581
Adjacent sequences: A152103 A152104 A152105 this_sequence A152107 A152108 A152109
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KEYWORD
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nonn
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AUTHOR
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Al Hakanson (hawkuu(AT)gmail.com), Nov 24 2008
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EXTENSIONS
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Extended beyond a(6) by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 26 2008
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