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!)
 A200335 a(n) = sqrt((A200216(n)+1)/5). 2
 137, 253772063, 472142416783537, 878420022140682133063, 1634298694352222684783778137, 3040609452244043180572708973082863, 5657047804679503550674811676317937783937, 10524926126507566387571141730985597902165021463 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All numbers (A200216(n)+1)/5 are perfect squares LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..50 FORMULA G.f.: (137 - 1116026*x + 137*x^2)/(1 - 1860497*x - 1860497*x^2 + x^3). a(n) = 1860497*a(n-1) + 1860497*a(n-2) - a(n-3). [corrected by Vincenzo Librandi, Nov 18 2011] MATHEMATICA aa = {}; uu = 682 + 61*Sqrt[125]; Do[vv = Expand[uu^(2*n - 1)]; tt = ((-1)^n vv[[1]] + 57)/125; xx = (5^5*tt^2 - 3000*tt + 719); yy = Round[N[Sqrt[xx^3], 1000]]; dd = xx^3 - yy^2; AppendTo[aa, Sqrt[(xx + 1)/5]], {n, 1, 20}]; aa PROG (Magma) I:=[137, 253772063, 472142416783537]; [n le 3 select I[n] else 1860497*Self(n-1)+1860497*Self(n-2)-Self(n-3): n in [1..30]]; // Vincenzo Librandi, Nov 18 2011 (PARI) x='x+O('x^30); Vec((137 -1116026*x +137*x^2)/(1 - 1860497*x - 1860497*x^2 + x^3)) \\ G. C. Greubel, Jul 10 2018 CROSSREFS Cf. A200216, A200217, A200218. Sequence in context: A064104 A300407 A122703 * A351237 A292094 A031964 Adjacent sequences: A200332 A200333 A200334 * A200336 A200337 A200338 KEYWORD nonn AUTHOR Artur Jasinski, Nov 16 2011 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 8 07:38 EST 2022. Contains 358691 sequences. (Running on oeis4.)