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A165225
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a(0)=1, a(1)=5, a(n)=10*a(n-1)-5*a(n-2) for n>1 .
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1
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1, 5, 45, 425, 4025, 38125, 361125, 3420625, 32400625, 306903125, 2907028125, 27535765625, 260822515625, 2470546328125, 23401350703125, 221660775390625, 2099601000390625, 19887706126953125, 188379056267578125
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| a(n+1)/a(n) -> 5+2sqrt(5)= 9,47213595...for n ->inf.
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FORMULA
| G.f.: (1-5x)/(1-10x+5x^2).
a(n) = ((5-2*sqrt(5))^n+(5+2*sqrt(5))^n)/2. [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Sep 25 2009]
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CROSSREFS
| Sequence in context: A022022 A058410 A005979 * A121272 A054318 A093140
Adjacent sequences: A165222 A165223 A165224 * A165226 A165227 A165228
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KEYWORD
| easy,nonn
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AUTHOR
| Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Sep 09 2009
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EXTENSIONS
| More terms from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Sep 25 2009
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