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A194513
Second coordinate of (2,7)-Lagrange pair for n.
3
-1, 0, -1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 4, 3, 4, 3, 4, 3, 4, 3, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 6, 5, 6, 5, 6, 5, 6, 5, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 10, 9, 10, 9, 10, 9, 10, 9, 10, 11, 10, 11
OFFSET
1,14
COMMENTS
See A194508.
FORMULA
From Chai Wah Wu, Jan 21 2020: (Start)
a(n) = a(n-1) + a(n-9) - a(n-10) for n > 10.
G.f.: x*(x^8 - x^7 + x^6 - x^5 + x^4 + x^3 - x^2 + x - 1)/(x^10 - x^9 - x + 1). (End)
a(n) = n - 2*floor((4*n + 6)/9). - Ridouane Oudra, Dec 28 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)... 4..1..5..2.-1..3..0..4..1..5...2...6...3
y(n).. -1..0.-1..0..1..0..1..0..1..0...1...0...1
MATHEMATICA
c = 2; d = 7;
x1 = {4, 1, 5, 2, -1, 3, 0, 4, 1}; y1 = {-1, 0, -1, 0, 1, 0, 1, 0, 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}] (* A194512 *)
Table[y[n], {n, 1, 100}] (* A194513 *)
Table[y[n], {n, 1, 100}]
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
Sequence in context: A096370 A330721 A076622 * A344018 A245040 A161314
KEYWORD
sign
AUTHOR
Clark Kimberling, Aug 28 2011
STATUS
approved