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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A165553 a(n) = (3/2)*(1+(-3)^(n-1)). 2

%I

%S 1,3,-3,15,-39,123,-363,1095,-3279,9843,-29523,88575,-265719,797163,

%T -2391483,7174455,-21523359,64570083,-193710243,581130735,-1743392199,

%U 5230176603,-15690529803,47071589415,-141214768239

%N a(n) = (3/2)*(1+(-3)^(n-1)).

%C a(n)/a(n-1) tends to -3.

%F a(0)=1, a(1)=3, a(n)=3*a(n-2)-2*a(n-1).

%F G.f.: (1+5x)/(1+2x-3x^2).

%F a(n)= Sum_{k=0..n} A112555(n,k)*2^(n-k).

%Y Cf. A046717, A084247.

%K easy,sign

%O 0,2

%A _Philippe Deléham_, Sep 21 2009

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 16 15:22 EDT 2021. Contains 348042 sequences. (Running on oeis4.)