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

 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!)
 A157287 a(n) = 1728*n - 24. 3
 1704, 3432, 5160, 6888, 8616, 10344, 12072, 13800, 15528, 17256, 18984, 20712, 22440, 24168, 25896, 27624, 29352, 31080, 32808, 34536, 36264, 37992, 39720, 41448, 43176, 44904, 46632, 48360, 50088, 51816, 53544, 55272, 57000, 58728 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The identity (10368*n^2 - 288*n + 1)^2 - (36*n^2-n)*(1728*n-24)^2 = 1 can be written as A157288(n)^2 - A157286(n)*a(n)^2 = 1 (see also second part of the initial comment in A157286). - Vincenzo Librandi, Jan 28 2012 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..10000 Vincenzo Librandi, X^2-AY^2=1 Index entries for linear recurrences with constant coefficients, signature (2,-1). FORMULA a(n) = 2*a(n-1) - a(n-2). - Vincenzo Librandi, Jan 28 2012 G.f.: x*(24*x+1704)/(x-1)^2. - Vincenzo Librandi, Jan 28 2012 MATHEMATICA LinearRecurrence[{2, -1}, {1704, 3432}, 40] (* Vincenzo Librandi, Jan 28 2012 *) PROG (Magma) I:=[1704, 3432]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]]; // Vincenzo Librandi, Jan 28 2012 (PARI) for(n=1, 40, print1(1728*n-24", ")); \\ Vincenzo Librandi, Jan 28 2012 CROSSREFS Cf. A157286, A157288. Sequence in context: A210121 A345506 A345782 * A029559 A222553 A345516 Adjacent sequences: A157284 A157285 A157286 * A157288 A157289 A157290 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Feb 27 2009 EXTENSIONS Comment rewritten by Bruno Berselli, Jan 28 2012 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.

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