OFFSET
0,3
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (0,2,0,0,0,-1).
FORMULA
G.f.: (1+x+x^3)/((1-x)*(1+x)*(1-x^2-x^4)). - Philippe Deléham, Jun 18 2013
a(n) = a(n-1) + a(n-3)*(1-(-1)^n)/2 + (1+(-1)^n)/2. - Paolo P. Lava, Jun 27 2013
MAPLE
f:= proc(n) option remember;
if n <= 1 then 1
elif n mod 2 = 0 then f(n-1)+1
else f(n-1)+f(n-3)
fi
end:
t21:=[seq(f(n), n=0..60)];
MATHEMATICA
LinearRecurrence[{0, 2, 0, 0, 0, -1}, {1, 1, 2, 3, 4, 6}, 50] (* Jean-François Alcover, Feb 13 2018 *)
PROG
(Haskell)
a226538 n = a226538_list !! n
a226538_list = concat $ transpose [drop 2 a000071_list, tail a001911_list]
-- Reinhard Zumkeller, Jun 18 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
V. T. Jayabalaji, Jun 10 2013
EXTENSIONS
Edited by N. J. A. Sloane, Jun 18 2013
STATUS
approved