A156636 a(n) = 4394*n + 1820.

1820, 6214, 10608, 15002, 19396, 23790, 28184, 32578, 36972, 41366, 45760, 50154, 54548, 58942, 63336, 67730, 72124, 76518, 80912, 85306, 89700, 94094, 98488, 102882, 107276, 111670, 116064, 120458, 124852, 129246, 133640, 138034, 142428

Offset

0,1

Comments

The identity (57122*n^2+47320*n+9801)^2-(169*n^2+140*n+29)*(4394*n+1820)^2=1 can be written as A156735(n)^2-A156640(n)*a(n)^2=1.

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

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

Formula

G.f.: 26*(70+99*x)/(x-1)^2. - R. J. Mathar, Jan 05 2011

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

Mathematica

LinearRecurrence[{2, -1}, {1820, 6214}, 50]

Prog

(Magma) I:=[1820, 6214]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]];
(PARI) a(n)=4394*n+1820 \\ Charles R Greathouse IV, Dec 23 2011

Crossrefs

Cf. A156640, AA156718, A156735.

Sequence in context: A338166 A353807 A326236 * A234660 A238030 A233719

Adjacent sequences: A156633 A156634 A156635 * A156637 A156638 A156639

Keyword

nonn,easy

Author

Vincenzo Librandi, Feb 15 2009

Extensions

Offset corrected by R. J. Mathar, Jan 05 2011

Status

approved