A157731 a(n) = 18522*n - 10248.

8274, 26796, 45318, 63840, 82362, 100884, 119406, 137928, 156450, 174972, 193494, 212016, 230538, 249060, 267582, 286104, 304626, 323148, 341670, 360192, 378714, 397236, 415758, 434280, 452802, 471324, 489846, 508368, 526890, 545412, 563934

Offset

1,1

Comments

The identity (388962*n^2 - 430416*n + 119071)^2 - (441*n^2 - 488*n + 135)*(18522*n - 10248)^2 = 1 can be written as A157732(n)^2 - A157730(n)*a(n)^2 = 1.

Links

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

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

Formula

G.f.: x*(8274 + 10248*x)/(1 - x)^2.

a(n) = 2*a(n-1) - a(n-2).

Mathematica

LinearRecurrence[{2, -1}, {8274, 26796}, 40]
18522 Range[40] - 10248 (* Harvey P. Dale, Nov 03 2017 *)

Prog

(Magma) I:=[8274, 26796]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..40]];
(PARI) a(n) = 18522*n - 10248.

Crossrefs

Cf. A157730, A157732.

Sequence in context: A166194 A269959 A188101 * A252581 A271748 A064014

Adjacent sequences: A157728 A157729 A157730 * A157732 A157733 A157734

Keyword

nonn,easy

Author

Vincenzo Librandi, Mar 05 2009

Status

approved