The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A124191 a(n) = ((2 + 3*sqrt(2))^n - (2 - 3*sqrt(2))^n)/(2*sqrt(2)). 0
 0, 3, 12, 90, 528, 3372, 20880, 130728, 815232, 5091120, 31777728, 198386592, 1238434560, 7731150528, 48262685952, 301286851200, 1880825008128, 11741315949312, 73296813911040, 457565678934528, 2856418110492672, 17831591947054080, 111316221335113728 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Index entries for linear recurrences with constant coefficients, signature (4,14). FORMULA From Philippe Deléham, Dec 12 2006: (Start) a(n) = 4*a(n-1) + 14*a(n-2) for n >= 2; a(0)=0, a(1)=3. G.f.: 3x/(1-4*x-14*x^2). (End) MATHEMATICA Expand[Table[((2 + 3Sqrt[2])^n - (2 - 3Sqrt[2])^n)/(2Sqrt[2]), {n, 0, 30}]] LinearRecurrence[{4, 14}, {0, 3}, 50] (* Amiram Eldar, Mar 29 2020 *) CROSSREFS Sequence in context: A266788 A039305 A174463 * A065087 A305870 A058337 Adjacent sequences:  A124188 A124189 A124190 * A124192 A124193 A124194 KEYWORD nonn,easy AUTHOR Artur Jasinski, Dec 10 2006 EXTENSIONS More terms from Amiram Eldar, Mar 29 2020 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 June 2 18:25 EDT 2020. Contains 334787 sequences. (Running on oeis4.)