OFFSET
0,2
COMMENTS
Column and row 1 of A206838.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000 (terms n = 1..210 from R. H. Hardin)
Index entries for linear recurrences with constant coefficients, signature (4,0,-2,1).
FORMULA
a(n) = 4*a(n-1) -2*a(n-3) +a(n-4).
G.f.: 1 / (1 - 4*x + 2*x^3 - x^4). - Colin Barker, Jul 05 2019
EXAMPLE
Some solutions for n=5
..3..1..2..1..0....1..0..0..0..0....2..2..1..1..0....1..1..3..3..0
MAPLE
a:= n-> (<<0|1|0|0>, <0|0|1|0>, <0|0|0|1>, <1|-2|0|4>>^n)[4$2]:
seq(a(n), n=0..25); # Alois P. Heinz, Oct 26 2016
PROG
(PARI) Vec(1 / (1 - 4*x + 2*x^3 - x^4) + O(x^26)) \\ Colin Barker, Jul 05 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Feb 13 2012
EXTENSIONS
a(0)=1 prepended by Alois P. Heinz, Oct 26 2016
STATUS
approved