OFFSET
0,3
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
T. D. Noe, Table of n, a(n) for n=0..400
R. K. Guy, William O. J. Moser, Numbers of subsequences without isolated odd members, Fibonacci Quarterly, 34, No. 2, 152-155 (1996).
Index entries for linear recurrences with constant coefficients, signature (0,3,0,2).
FORMULA
a(n) = 3*a(n-2) + 2*a(n-4).
G.f. = (1 + x + 2 x^3)/(1 - 3 x^2 - 2 x^4). - Harvey P. Dale, Feb 18 2011, edited by M. F. Hasler, Jun 19 2019
MATHEMATICA
CoefficientList[Series[(-1-x-2 x^3)/(-1+3 x^2+2 x^4), {x, 0, 40}], x] (* Harvey P. Dale, Feb 18 2011 *)
LinearRecurrence[{0, 3, 0, 2}, {1, 1, 3, 5}, 40] (* Harvey P. Dale, Feb 10 2015 *)
PROG
(Haskell)
a007455_list = 1 : 1 : 3 : 5 : zipWith (+)
(map (* 2) a007455_list) (map (* 3) $ drop 2 a007455_list)
a007455 n = a007455_list !! n
-- Reinhard Zumkeller, Jul 16 2012
(PARI) A007455(n)=[n%2*2+3, 1]*([3, 1; 2, 0]^(n\2-1))[, 1] \\ M. F. Hasler, Jun 19 2019
CROSSREFS
KEYWORD
nonn,easy,nice
AUTHOR
STATUS
approved