The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A133646 a(n)=5*a(n-1)+30*a(n-2) for n>=3, a(0)=1, a(1)=5, a(2)=50 . 2
 1, 5, 50, 400, 3500, 29500, 252500, 2147500, 18312500, 155987500, 1329312500, 11326187500, 96510312500, 822337187500, 7006995312500, 59705092187500, 508735320312500, 4334829367187500, 36936206445312500, 314725913242187500 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS FORMULA G.f.: (1-5*x^2)/(1-5*x-30*x^2) . a(n) = Sum_{k, 0<=k<=n}A122950(n,k)*5^k . a(n)=(5/2)*[(5/2)-(1/2)*sqrt(145)]^(n-1)-(15/58)*[(5/2)-(1/2)*sqrt(145)]^(n-1)*sqrt(145)+(15/58)*sqrt(145) *[(5/2)+(1/2)*sqrt(145)]^(n-1)+(5/2)*[(5/2)+(1/2)*sqrt(145)]^(n-1)+(1/6)*[C(2*n,n) mod 2], with n>=0 CROSSREFS Sequence in context: A227261 A036291 A060347 * A043032 A247771 A125962 Adjacent sequences: A133643 A133644 A133645 * A133647 A133648 A133649 KEYWORD easy,nonn AUTHOR Philippe Deléham, Dec 31 2007 EXTENSIONS Corrected formula. - Paolo P. Lava, Nov 24 2008 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 February 3 14:36 EST 2023. Contains 360035 sequences. (Running on oeis4.)