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840, 1681, 2522, 3363, 4204, 5045, 5886, 6727, 7568, 8409, 9250, 10091, 10932, 11773, 12614, 13455, 14296, 15137, 15978, 16819, 17660, 18501, 19342, 20183, 21024, 21865, 22706, 23547, 24388, 25229, 26070, 26911, 27752, 28593, 29434
(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 a(n)^2-A158401(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 (2,-1).
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FORMULA
| a(n) = 2*a(n-1)-a(n-2).
G.f.: x*(840+x)/(1-x)^2.
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MATHEMATICA
| LinearRecurrence[{2, -1}, {840, 1681}, 50]
841 Range[40]-1 [From Harvey P. Dale, Jan. 29, 2011]
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PROG
| (MAGMA) I:=[840, 1681]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]];
(PARI) a(n) = 841*n - 1.
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CROSSREFS
| Cf. A158401.
Sequence in context: A179670 A092002 A169827 * A045477 A005952 A177021
Adjacent sequences: A158399 A158400 A158401 * A158403 A158404 A158405
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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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