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A157734
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441n^2 - 394n + 88.
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3
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135, 1064, 2875, 5568, 9143, 13600, 18939, 25160, 32263, 40248, 49115, 58864, 69495, 81008, 93403, 106680, 120839, 135880, 151803, 168608, 186295, 204864, 224315, 244648, 265863, 287960, 310939, 334800, 359543, 385168, 411675, 439064
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The identity (388962*n^2-347508*n+77617)^2-(441*n^2-394*n+88)*(18522*n-8274)^2=1 can be written as A157736(n)^2-a(n)*A157735(n)^2=1.
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Vincenzo Librandi, X^2-AY^2=1
Index to sequences with linear recurrences with constant coefficients, signature (3,-3,1).
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FORMULA
| a(n) = 3*a(n-1) -3*a(n-2) +a(n-3).
G.f.: x*(-135-659*x-88*x^2)/(x-1)^3.
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MATHEMATICA
| LinearRecurrence[{3, -3, 1}, {135, 1064, 2875}, 40]
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PROG
| (MAGMA) I:=[135, 1064, 2875]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..40]];
(PARI) a(n) = 441*n^2 - 394*n + 88.
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CROSSREFS
| Cf. A157735, A157736.
Sequence in context: A050215 A176313 A159201 * A061073 A195671 A004005
Adjacent sequences: A157731 A157732 A157733 * A157735 A157736 A157737
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KEYWORD
| nonn,easy
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 05 2009
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