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!)
A178936 Floor((2*3^n+3*2^n)/5). 3

%I

%S 1,2,6,15,42,116,330,951,2778,8180,24234,72087,215034,642644,1923018,

%T 5759223,17258010,51734708,155125482,465219159,1395342906,4185399572,

%U 12554940426,37662304695,112981880922,338935576436,1016786596650,3050319524631,9150878043258

%N Floor((2*3^n+3*2^n)/5).

%H Vincenzo Librandi, <a href="/A178936/b178936.txt">Table of n, a(n) for n = 0..2000</a>

%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (5,-6,0,1,-5,6).

%F G.f.: (1-3*x+2*x^2-3*x^3+2*x^4-x^5)/(1-5*x+6*x^2-x^4+5*x^5-6*x^6) = (1-3*x+2*x^2-3*x^3+2*x^4-x^5)/((1-2*x)*(1-3*x)*(1-x^4)).

%F Recurrence: a(n+6) = 5*a(n+5)-6*a(n+4)+a(n+2)-5*a(n+1)+6*a(n).

%F a(n) = (8*3^n+12*2^n-(1-(-1)^n)*(5+i^(n+1)))/20, where i=sqrt(-1). - Bruno Berselli, Sep 05 2011

%o (Maxima) makelist(floor((2*3^n+3*2^n)/5),n,0,12);

%o (MAGMA) [Floor((2*3^n+3*2^n)/5): n in [0..30]]; // Vincenzo Librandi, Sep 06 2011

%Y Cf. A178934, A178935.

%K nonn,easy

%O 0,2

%A _Emanuele Munarini_, Dec 30 2010

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 February 25 22:37 EST 2021. Contains 341618 sequences. (Running on oeis4.)