OFFSET
0,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (-1, 4, 4).
FORMULA
a(2*n)=5-2^(2*n), a(2*n+1)=10-3*a(2n).
a(n)+a(n+1)=A135520(n).
a(n) = 1/6*2^n*a(0) + 1/4*2^n*a(1) - 1/2*a(0)*(-2)^n - 1/3*(-1)^n*a(2) - 1/4*a(1)*(-2)^n + 4/3*(-1)^n*a(0) + 1/4*(-2)^n*a(2) + 1/12*2^n*a(2). - Alexander R. Povolotsky, Mar 31 2008
G.f.: (4+2*x-17*x^2)/((1+2*x)*(1-2*x)*(1+x)). a(n)=2^(n-2)+5*(-1)^n*(1-2^(n-2)). - R. J. Mathar, Jun 15 2009
a(n)=(5*(-2)^n-40*(-1)^n+2^n)/8. - Harvey P. Dale, Jun 10 2011
MATHEMATICA
LinearRecurrence[{-1, 4, 4}, {4, -2, 1}, 50] (* or *) Table[(5(-2)^n- 40(-1)^n+2^n)/8, {n, 50}] (* Harvey P. Dale, Jun 10 2011 *)
PROG
(Magma) [2^(n-2)+5*(-1)^n*(1-2^(n-2)): n in [0..40]]; // Vincenzo Librandi, Aug 09 2011
CROSSREFS
KEYWORD
sign
AUTHOR
Paul Curtz, Mar 17 2008
EXTENSIONS
Edited by N. J. A. Sloane, Apr 18 2008
More terms from Harvey P. Dale, Jun 10 2011
STATUS
approved