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Search: id:A015581
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| A015581 |
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a(n) = 9 a(n-1) + 5 a(n-2). |
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+0
2
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| 0, 1, 9, 86, 819, 7801, 74304, 707741, 6741189, 64209406, 611590599, 5825362421, 55486214784, 528502745161, 5033955780369, 47948115749126, 456702820643979, 4350065964541441, 41434107784092864
(list; graph; listen)
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OFFSET
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0,3
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FORMULA
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A linear 2nd order recurrence.
O.g.f: -x/(-1+9*x+5*x^2) . - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Dec 02 2007
a(n)=(1/101)*sqrt(101)*{[(9/2)+(1/2)*sqrt(101)]^n-[(9/2)-(1/2)*sqrt(101)]^n}, with n>=0 [From Paolo P. Lava (ppl(AT)spl.at), Jan 13 2009]
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PROGRAM
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(Other) sage: [lucas_number1(n, 9, -5) for n in xrange(0, 19)]# [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 26 2009]
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CROSSREFS
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Sequence in context: A152106 A142982 A029711 this_sequence A152261 A028339 A100814
Adjacent sequences: A015578 A015579 A015580 this_sequence A015582 A015583 A015584
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KEYWORD
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nonn,easy
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AUTHOR
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Olivier Gerard (olivier.gerard(AT)gmail.com)
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