login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A158230 256n^2+2n. 2
258, 1028, 2310, 4104, 6410, 9228, 12558, 16400, 20754, 25620, 30998, 36888, 43290, 50204, 57630, 65568, 74018, 82980, 92454, 102440, 112938, 123948, 135470, 147504, 160050, 173108, 186678, 200760, 215354, 230460, 246078, 262208, 278850, 296004 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The identity (256*n+1)^2-(256*n^2+2*n)*(16)^2=1 can be written as A158231(n)^2-a(n)*(16)^2=1.

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*(16^2*t+2)).

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

a(n) = 3*a(n-1) -3*a(n-2) +a(n-3).

G.f.: x*(-254*x-258)/(x-1)^3.

MATHEMATICA

LinearRecurrence[{3, -3, 1}, {258, 1028, 2310}, 50]

PROG

(Magma) I:=[258, 1028, 2310]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..50]];

(PARI) a(n) = 256*n^2+2*n.

CROSSREFS

Cf. A158231.

Sequence in context: A339538 A252264 A202892 * A209945 A233306 A282060

Adjacent sequences: A158227 A158228 A158229 * A158231 A158232 A158233

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Mar 14 2009

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 3 09:50 EST 2022. Contains 358517 sequences. (Running on oeis4.)