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A281503
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Solutions x to the negative Pell equation y^2 = 33*x^2 - 8 with x,y >= 0.
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2
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1, 3, 43, 137, 1977, 6299, 90899, 289617, 4179377, 13316083, 192160443, 612250201, 8835201001, 28150193163, 406227085603, 1294296635297, 18677610736737, 59509495030499, 858763866804299, 2736142474767657, 39484460262261017, 125803044344281723
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = 46*a(n-2) - a(n-4) for n>4.
G.f.: x*(1 - x)*(1 + 4*x + x^2) / (1 - 46*x^2 + x^4).
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EXAMPLE
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3 is in the sequence because (x, y) = (3, 17) is a solution to y^2 = 33*x^2 - 8.
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MATHEMATICA
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LinearRecurrence[{0, 46, 0, -1}, {1, 3, 43, 137}, 30] (* Harvey P. Dale, Mar 22 2022 *)
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PROG
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(PARI) Vec(x*(1 - x)*(1 + 4*x + x^2) / (1 - 46*x^2 + x^4) + O(x^30))
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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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STATUS
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approved
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