OFFSET
4,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 4..500
Index entries for linear recurrences with constant coefficients, signature (2,-1,1,-1).
FORMULA
G.f.: -x^4*(-13+6*x-3*x^2+8*x^3) / ( (x-1)*(x^3+x-1) ). - R. J. Mathar, Jan 19 2011
a(n) = a(n-1) + a(n-3) + 2 for n>6. - Greg Dresden, Feb 09 2020
MATHEMATICA
LinearRecurrence[{2, -1, 1, -1}, {13, 20, 30, 45}, 40] (* Harvey P. Dale, Aug 12 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 14 2009
STATUS
approved