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839, 3360, 7563, 13448, 21015, 30264, 41195, 53808, 68103, 84080, 101739, 121080, 142103, 164808, 189195, 215264, 243015, 272448, 303563, 336360, 370839, 407000, 444843, 484368, 525575, 568464, 613035, 659288, 707223, 756840, 808139, 861120
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The identity (841*n-1)^2-(841*n^2-2*n)*(29)^2=1 can be written as A158402(n)^2-a(n)*(29)^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
E. J. Barbeau, Polynomial Excursions, Chapter 10: Diophantine equations (2010), pages 84-85 (row 15 in the first table at p. 85, case d(t) = t*(29^2*t-2)).
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*(-839-843*x)/(x-1)^3.
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MATHEMATICA
| LinearRecurrence[{3, -3, 1}, {839, 3360, 7563}, 50]
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PROG
| (MAGMA) I:=[839, 3360, 7563]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..50]];
(PARI) a(n) = 841*n^2 - 2*n.
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CROSSREFS
| Cf. A158402.
Sequence in context: A202716 A118380 A135639 * A156937 A135640 A095119
Adjacent sequences: A158398 A158399 A158400 * A158402 A158403 A158404
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KEYWORD
| nonn,easy
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 18 2009
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