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A280761
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Solutions y_n to the negative Pell equation y^2 = 72*x^2 - 8.
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2
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8, 280, 9512, 323128, 10976840, 372889432, 12667263848, 430314081400, 14618011503752, 496582077046168, 16869172608065960, 573055286597196472, 19467010571696614088, 661305304151087682520, 22464913330565284591592, 763145747935068588431608
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OFFSET
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0,1
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COMMENTS
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Although this is a list, it has offset zero because one of the references numbered the solutions starting at 0.
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LINKS
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FORMULA
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a(n) = 34*a(n-1) - a(n-2), a(0)=8, a(1)=280. - Seiichi Manyama, Jan 17 2017
a(n) = (17+12*sqrt(2))^(-n)*(-4-3*sqrt(2) + (-4+3*sqrt(2))*(17+12*sqrt(2))^(2*n)) for n>0. - Colin Barker, Jan 17 2017
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MATHEMATICA
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PROG
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(Magma) I:=[8, 280]; [n le 2 select I[n] else 34*Self(n-1)-Self(n-2): n in [1..20]]; // Vincenzo Librandi, Jan 18 2017
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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