This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A157859 a(n) = 103680000*n^2 - 28800*n + 1. 3
 103651201, 414662401, 933033601, 1658764801, 2591856001, 3732307201, 5080118401, 6635289601, 8397820801, 10367712001, 12544963201, 14929574401, 17521545601, 20320876801, 23327568001, 26541619201, 29963030401, 33591801601 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The identity (103680000*n^2 - 28800*n + 1)^2 - (3600*n^2 - n)*(1728000*n - 240)^2 = 1 can be written as a(n)^2 - A157857(n)*A157858(n)^2 = 1 (see second comment at A157858). - Vincenzo Librandi, Jan 25 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 (3, -3, 1). FORMULA a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Vincenzo Librandi, Jan 25 2012 G.f.: x*(-103651201 - 103708798*x - x^2)/(x-1)^3. - Vincenzo Librandi, Jan 25 2012 MATHEMATICA LinearRecurrence[{3, -3, 1}, {103651201, 414662401, 933033601}, 40] (* Vincenzo Librandi, Jan 25 2012 *) PROG (MAGMA) I:=[103651201, 414662401, 933033601]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Jan 25 2012 (PARI) for(n=1, 22, print1(103680000*n^2 - 28800*n + 1", ")); \\ Vincenzo Librandi, Jan 25 2012 CROSSREFS Cf. A157857, A157858. Sequence in context: A241792 A112717 A114679 * A157863 A035498 A018897 Adjacent sequences:  A157856 A157857 A157858 * A157860 A157861 A157862 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Mar 08 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 9 17:18 EST 2019. Contains 329879 sequences. (Running on oeis4.)