OFFSET
1,1
COMMENTS
For an introduction to reductions of polynomials by substitutions such as x^2->x+1, see A192232.
LINKS
Yuanan Diao, Michael Finney, and Dawn Ray, The number of oriented rational links with a given deficiency number, arXiv:2007.02819 [math.GT], 2020. See p. 16.
FORMULA
Empirical G.f.: -2*x*(x^2 - 3*x + 1) / ((x - 1)*(x + 1)*(2*x - 1)*(4*x - 1)). - Colin Barker, Nov 12 2012
Conjectures from Colin Barker, Feb 14 2017: (Start)
a(n) = (-1 - (-1)^n + 2^n + 4^n) / 3.
a(n) = 6*a(n-1) - 7*a(n-2) - 6*a(n-3) + 8*a(n-4) for n>4.
(End)
EXAMPLE
MATHEMATICA
(See A192465.)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jul 01 2011
STATUS
approved