OFFSET
1,7
COMMENTS
See A194508.
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,0,0,1,-1).
FORMULA
From Chai Wah Wu, Jan 21 2020: (Start)
a(n) = a(n-1) + a(n-8) - a(n-9) for n > 9.
G.f.: -x*(x^3 + x - 1)*(x^4 - 2*x^3 + x - 1)/(x^9 - x^8 - x + 1). (End)
a(n) = 2*n - 3*floor((5*n + 4)/8). - Ridouane Oudra, Dec 29 2020
EXAMPLE
This table shows (x(n),y(n)) for 1<=n<=13:
n...... 1..2..3..4..5..6..7..8..9..10..11..12..13
x(n)... 2.-1..1..3..0..2.-1..1..3..0...2...4...1
y(n).. -1..1..0.-1..1..0..2..1..0..2...1...0...2
MATHEMATICA
c = 3; d = 5;
x1 = {2, -1, 1, 3, 0, 2, -1, 1}; y1 = {-1, 1, 0, -1, 1, 0, 2, 1};
x[n_] := If[n <= c + d, x1[[n]], x[n - c - d] + 1]
y[n_] := If[n <= c + d, y1[[n]], y[n - c - d] + 1]
Table[x[n], {n, 1, 100}] (* A194516 *)
Table[y[n], {n, 1, 100}] (* A194517 *)
r[1, n_] := n; r[2, n_] := x[n]; r[3, n_] := y[n]
TableForm[Table[r[m, n], {m, 1, 3}, {n, 1, 30}]]
CROSSREFS
KEYWORD
sign
AUTHOR
Clark Kimberling, Aug 28 2011
STATUS
approved