OFFSET
1,3
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..1000
FORMULA
From Chai Wah Wu, Jun 10 2020: (Start)
a(n) = 2*a(n-1) - a(n-2) + a(n-16) - 2*a(n-17) + a(n-18) for n > 18.
G.f.: x*(-x^14 - x^12 - x^11 - x^9 - x^6 - x^4 - x)/(x^18 - 2*x^17 + x^16 - x^2 + 2*x - 1). (End)
MATHEMATICA
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Aug 20 2011
STATUS
approved