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 (2,0,0,-2,1,-1,1).
FORMULA
G.f.: -x^4*(13-5*x-7*x^2-12*x^3+6*x^4-4*x^5+8*x^6) / ( (x^5+x^4+2*x^3+x^2-1)*(x-1)^2 ). - R. J. Mathar, Jan 19 2011
a(n) = 2*a(n-1)-2*a(n-4)+a(n-5)-a(n-6)+a(n-7). [Harvey P. Dale, May 06 2011]
MATHEMATICA
LinearRecurrence[{2, 0, 0, -2, 1, -1, 1}, {13, 21, 35, 58, 96, 159, 264}, 40] (*Harvey P. Dale, May 06 2011 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. H. Hardin, Aug 14 2009
STATUS
approved