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Search: id:A132593
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| A132593 |
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Sequence allows us to find X values of the equation: X(X + 1) - 10*Y^2 = 0. |
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+0
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| 0, 9, 360, 13689, 519840, 19740249, 749609640, 28465426089, 1080936581760, 41047124680809, 1558709801289000, 59189925324301209, 2247658452522156960, 85351831270517663289, 3241121929827149048040, 123077281502161146162249
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OFFSET
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0,2
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FORMULA
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a(0)=0, a(1)=9 and a(n)=38*a(n-1) - a(n-2) + 18.
a(n)=-1/2+(1/4)*[19-6*sqrt(10)]^n+(1/4)*[19+6*sqrt(10)]^n, with n>=0 - Paolo P. Lava (ppl(AT)spl.at), Jul 11 2008
a(n) = (A078986(n) - 1)/2 [From Max Alekseyev (maxale(AT)gmail.com), Nov 13 2009]
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CROSSREFS
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Cf. A007654.
Sequence in context: A119756 A063068 A130558 this_sequence A162133 A162084 A051848
Adjacent sequences: A132590 A132591 A132592 this_sequence A132594 A132595 A132596
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KEYWORD
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nonn,new
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AUTHOR
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Mohamed Bouhamida (bhmd95(AT)yahoo.fr), Nov 14 2007
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EXTENSIONS
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More terms from Max Alekseyev (maxale(AT)gmail.com), Nov 13 2009
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