OFFSET
0,4
COMMENTS
LINKS
Clark Kimberling, Table of n, a(n) for n = 0..2000
Index entries for linear recurrences with constant coefficients, signature (1, 3, -2, -2)
FORMULA
a(n) = a(n-1) + a(n-3) + a(n-4), where a(0) = 0, a(1) = 0, a(2) = 1, a(3) = 2.
G.f.: (x^2 (1 + x))/((-1 + x + x^2) (-1 + 2 x^2)).
MATHEMATICA
LinearRecurrence[{1, 3, -2, -2}, {0, 0, 1, 2}, 100]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Nov 29 2017
STATUS
approved