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A156865
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729000n - 612180.
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4
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116820, 845820, 1574820, 2303820, 3032820, 3761820, 4490820, 5219820, 5948820, 6677820, 7406820, 8135820, 8864820, 9593820, 10322820, 11051820, 11780820, 12509820, 13238820, 13967820, 14696820, 15425820, 16154820, 16883820
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The identity(32805000*n^2-55096200*n+23133601)^2-(2025*n^2-649*n+52)*(729000*n-612180)^2=1 can be written as A157078(n)^2-A156853(n)*a(n)^2=1.
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Index to sequences with linear recurrences with constant coefficients, signature (2,-1).
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FORMULA
| a(n) = 2*a(n-1) - a(n-2).
G.f. 180*x*(649+3401*x)/(x-1)^2.
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MATHEMATICA
| LinearRecurrence[{2, -1}, {116820, 845820}, 40]
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PROG
| (MAGMA) I:=[116820, 845820]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..40]];
(PARI) a(n)=729000*n-612180 \\ Charles R Greathouse IV, Dec 23 2011
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CROSSREFS
| Cf. A156853, A157078.
Sequence in context: A172783 A046407 A156417 * A206204 A204075 A016926
Adjacent sequences: A156862 A156863 A156864 * A156866 A156867 A156868
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KEYWORD
| nonn,easy
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Feb 17 2009
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