OFFSET
0,5
COMMENTS
LINKS
Index entries for linear recurrences with constant coefficients, signature (4,0,-4,-12,-8,-4).
FORMULA
G.f.: z^3/(1-2z-2z^2-2z^3)^2.
EXAMPLE
a(4)=4 because we have 0001, 0002, 1000 and 2000.
MAPLE
h:=z^3/(1-2*z-2*z^2-2*z^3)^2: hser:=series(h, z=0, 33): seq(coeff(hser, z, n), n=0..30);
MATHEMATICA
LinearRecurrence[{4, 0, -4, -12, -8, -4}, {0, 0, 0, 1, 4, 16}, 40] (* Harvey P. Dale, Jan 28 2021 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, May 26 2006
STATUS
approved