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360, 721, 1082, 1443, 1804, 2165, 2526, 2887, 3248, 3609, 3970, 4331, 4692, 5053, 5414, 5775, 6136, 6497, 6858, 7219, 7580, 7941, 8302, 8663, 9024, 9385, 9746, 10107, 10468, 10829, 11190, 11551, 11912, 12273, 12634, 12995, 13356, 13717, 14078
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The identity (361*n-1)^2-(361*n^2-2*n)*(19)^2=1 can be written as a(n)^2-A158307(n)*(19)^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*(19^2*t-2)).
Index to sequences with linear recurrences with constant coefficients, signature (2,-1).
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FORMULA
| G.f.: x*(360+x)/(1-x)^2.
a(0)=360, a(1)=721, a(n)=2*a(n-1)-a(n-2) [From Harvey P. Dale, Aug 18 2011]
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MATHEMATICA
| 361*Range[40]-1 (* or *) LinearRecurrence[{2, -1}, {360, 721}, 40] (* From Harvey P. Dale, Aug 18 2011 *)
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PROG
| (MAGMA) I:=[360, 721]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]];
(PARI) a(n) = 361*n - 1.
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CROSSREFS
| Cf. A158307.
Sequence in context: A048978 A056502 A056492 * A205738 A112536 A140801
Adjacent sequences: A158305 A158306 A158307 * A158309 A158310 A158311
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KEYWORD
| nonn,easy
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 16 2009
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