OFFSET
1,1
COMMENTS
Column 1 of A183262
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
a(n) = [x^n] f(n,x) where f(1,x) = 2*x, f(2,x) = x^3+x^2+2*x, and f(n,x) = (1-x^3)*f(n-2,x) + (x+x^2)*f(n-1,x) otherwise. - Robert Israel, Nov 13 2019
EXAMPLE
All solutions for 5X1
..0....0....1....1....0....1....0
..0....1....0....1....0....1....0
..1....0....0....1....1....1....0
..1....0....0....0....0....1....1
..1....0....1....0....0....1....0
MAPLE
fx:= proc(n) option remember; expand((1-x^3)*procname(n-2)+(x+x^2)*procname(n-1)) end proc:
fx(0):= 0: fx(1):= 2*x: fx(2):= x^3 + x^2 + 2*x:
seq(coeff(fx(n), x, n), n=1..40); # Robert Israel, Nov 13 2019
MATHEMATICA
fx[n_] := fx[n] = Expand[(1-x^3)*fx[n-2] + (x+x^2)*fx[n-1]];
fx[0] = 0; fx[1] = 2x; fx[2] = x^3 + x^2 + 2x;
Table[Coefficient[fx[n], x, n], {n, 1, 40}] (* Jean-François Alcover, Aug 29 2022, after Robert Israel *)
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 03 2011
STATUS
approved