This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A169724 (2*3^(n-1)+1)^2. 1
 9, 49, 361, 3025, 26569, 237169, 2128681, 19140625, 172213129, 1549760689, 13947373801, 125524947025, 1129720271689, 10167469690609, 91507188951721, 823564585774225, 7412080927594249, 66708727315226929, 600378542737678441, 5403406875341014225 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A subsequence of the squares A000290. Essentially equal to A052919(n)^2. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 Alice V. Kleeva, Grid for this sequence Alice V. Kleeva, Illustration of initial terms Index to sequences with linear recurrences with constant coefficients, signature (13,-39,27). FORMULA a(n)= +13*a(n-1) -39*a(n-2) +27*a(n-3). G.f.: x*( -9+68*x-75*x^2 ) / ( (x-1)*(3*x-1)*(9*x-1) ). [R. J. Mathar, Apr 26 2010] MATHEMATICA CoefficientList[Series[(-9 + 68 x - 75 x^2)/((x - 1) (3 x - 1) (9 x - 1)), {x, 0, 40}], x] (* Vincenzo Librandi, Dec 03 2012 *) PROG (MAGMA) I:=[9, 49, 361]; [n le 3 select I[n] else 13*Self(n-1) - 39*Self(n-2) + 27*Self(n-3): n in [1..30]]; // Vincenzo Librandi, Dec 03 2012 CROSSREFS Cf. A169720-A169727, A100702. Sequence in context: A188235 A066558 A168597 * A135625 A160603 A115326 Adjacent sequences:  A169721 A169722 A169723 * A169725 A169726 A169727 KEYWORD nonn,easy AUTHOR Alice V. Kleeva (alice27353(AT)gmail.com), Jan 19 2010 EXTENSIONS G.f. adapted to the offset by Vincenzo Librandi, Dec 03 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .