OFFSET
1,2
COMMENTS
LINKS
Index entries for linear recurrences with constant coefficients, signature (2,6,2,-1).
FORMULA
a(n) = 2*a(n-1) + 6*a(n-2) + 2*a(n-3) - a(n-4). - Colin Barker, Dec 09 2012
G.f.: 2*x^2 / ((x+1)^2*(x^2-4*x+1)). - Colin Barker, Dec 09 2012
EXAMPLE
MATHEMATICA
See A192376.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jun 29 2011
STATUS
approved