This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A124191 a(n)=((2 + 3Sqrt[2])^n - (2 - 3Sqrt[2])^n)/(2Sqrt[2]). 0
 0, 3, 12, 90, 528, 3372, 20880, 130728, 815232, 5091120, 31777728, 198386592, 1238434560, 7731150528, 48262685952, 301286851200, 1880825008128, 11741315949312, 73296813911040 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Index entries for linear recurrences with constant coefficients, signature (4,14). FORMULA a(0)=0, a(1)=3, a(n)=4*a(n-1)+14*a(n-2) for n>=2 . G.f.:3x/(1-4*x-14*x^2) - Philippe Deléham, Dec 12 2006 a(n)=-(1/4)*sqrt(2)*[2-3*sqrt(2)]^n+(1/4)*[2+3*sqrt(2)]^n*sqrt(2), with n>=0 [From Paolo P. Lava, Oct 07 2008] MATHEMATICA Expand[Table[((2 + 3Sqrt[2])^n - (2 - 3Sqrt[2])^n)/(2Sqrt[2]), {n, 0, 30}]] (*Artur Jasinski*) 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 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 September 16 08:36 EDT 2019. Contains 327091 sequences. (Running on oeis4.)