OFFSET
0,3
LINKS
G. Nebe, E. M. Rains and N. J. A. Sloane, Self-Dual Codes and Invariant Theory, Springer, Berlin, 2006.
Index entries for linear recurrences with constant coefficients, signature (2,-1).
FORMULA
The even numbers >= 4, prefixed by 1, 1, 3.
From R. J. Mathar, Dec 15 2008: (Start)
G.f.: 1+x+3*x^2+(4-2*x)*x^3/(1-x)^2.
a(n) = A004278(n) for n<>1. (End)
E.g.f.: 3 + 2*exp(x)*(x - 1) + x + x^2/2. - Stefano Spezia, Sep 17 2025
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Apr 08 2004
STATUS
approved
