OFFSET
0,2
COMMENTS
LINKS
Clark Kimberling, Table of n, a(n) for n = 0..1999
Index entries for linear recurrences with constant coefficients, signature (1,0,1,1).
FORMULA
a(n) = a(n-1) + a(n-3) + a(n-4), where a(0) = 1, a(1) = 2, a(2) = 3, a(3) = 4.
G.f.: (-1 - x - x^2)/(-1 + x + x^3 + x^4).
From Greg Dresden, Aug 25 2021: (Start)
a(2*n) = a(2*n - 1) + a(2*n - 2),
a(2*n) = 2*F(n+1)^2 - (-1)^n = A061646(n+1),
MATHEMATICA
LinearRecurrence[{1, 0, 1, 1}, {1, 2, 3, 4}, 100]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Nov 25 2017
STATUS
approved