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A157375
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2401n^2 - 980n + 99.
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3
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1520, 7743, 18768, 34595, 55224, 80655, 110888, 145923, 185760, 230399, 279840, 334083, 393128, 456975, 525624, 599075, 677328, 760383, 848240, 940899, 1038360, 1140623, 1247688, 1359555, 1476224, 1597695, 1723968, 1855043, 1990920
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The identity (2401*n^2-980*n+99)^2-(49*n^2-20*n +2)*(343*n-70)^2=1 can be written as a(n)^2-A157373(n)*A157374(n)^2=1. - Vincenzo Librandi, Jan 28 2012
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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). - Vincenzo Librandi, Jan 28 2012
G.f.: x*(-1520-3183*x-99*x^2)/(x-1)^3. - Vincenzo Librandi, Jan 28 2012
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MATHEMATICA
| LinearRecurrence[{3, -3, 1}, {1520, 7743, 18768}, 40] (* Vincenzo Librandi, Jan 28 2012 *)
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PROG
| (MAGMA) I:=[1520, 7743, 18768]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Jan 28 2012
(PARI) for(n=1, 40, print1(2401*n^2 - 980*n + 99", ")); \\ Vincenzo Librandi, Jan 28 2012
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CROSSREFS
| Cf. A157373, A157374.
Sequence in context: A206654 A112641 A203386 * A174746 A074906 A025413
Adjacent sequences: A157372 A157373 A157374 * A157376 A157377 A157378
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KEYWORD
| nonn,easy
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Feb 28 2009
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