OFFSET
0,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (6,-4,-8).
FORMULA
a(n) = ((2+sqrt(8))^n+(2-sqrt(8))^n-2^(n+1))/8; E.g.f.: exp(2x)(sinh(sqrt(2)*x))^2/2 = (exp(x)*sinh(sqrt(2)*x)/sqrt(2))^2. - Paul Barry, May 16 2003
G.f.: 2*x^2 / ( (2*x-1)*(4*x^2+4*x-1) ). - R. J. Mathar, Nov 24 2012
a(n) = 2^(n-3)*(A002203(n) - 2). - Vladimir Reshetnikov, Oct 07 2016
MATHEMATICA
Table[2^(n-3)*(LucasL[n, 2] - 2), {n, 0, 20}] (* Vladimir Reshetnikov, Oct 07 2016 *)
PROG
(Magma) [Floor(((2+Sqrt(8))^n+(2-Sqrt(8))^n-2^(n+1))/8): n in [0..30] ]; // Vincenzo Librandi, Aug 20 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved