A158004 a(n) = 392*n - 1.

391, 783, 1175, 1567, 1959, 2351, 2743, 3135, 3527, 3919, 4311, 4703, 5095, 5487, 5879, 6271, 6663, 7055, 7447, 7839, 8231, 8623, 9015, 9407, 9799, 10191, 10583, 10975, 11367, 11759, 12151, 12543, 12935, 13327, 13719, 14111, 14503, 14895

Offset

1,1

Comments

The identity (392*n - 1)^2 - (196*n^2 - n)*28^2 = 1 can be written as a(n)^2 - A158003(n)*28^2 = 1. - Vincenzo Librandi, Feb 10 2012

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

E. J. Barbeau, Polynomial Excursions, Chapter 10: Diophantine equations (2010), pages 84-85 (row 14 in the first table at p. 85, case d(t) = t*(14^2*t-1)).

Index entries for linear recurrences with constant coefficients, signature (2,-1).

Formula

G.f.: x*(x+391)/(x-1)^2. - Vincenzo Librandi, Feb 10 2012

a(n) = 2*a(n-1) - a(n-2). - Vincenzo Librandi, Feb 10 2012

Mathematica

392Range[40]-1 (* Harvey P. Dale, Nov 14 2011 *)
LinearRecurrence[{2, -1}, {391, 783}, 50] (* Vincenzo Librandi, Feb 10 2012 *)

Prog

(Magma) I:=[391, 783]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]]; // Vincenzo Librandi, Feb 10 2012
(PARI) for(n=1, 50, print1(392*n - 1", ")); \\ Vincenzo Librandi, Feb 10 2012

Crossrefs

Cf. A158003.

Sequence in context: A332419 A207575 A318174 * A264448 A160184 A187724

Adjacent sequences: A158001 A158002 A158003 * A158005 A158006 A158007

Keyword

nonn,easy

Author

Vincenzo Librandi, Mar 11 2009

Status

approved