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A272664
(001)(001)(001)(10)*.
1
0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0
OFFSET
0
COMMENTS
Three copies of 001 followed by infinitely many copies of 10.
Lexicographically least binary sequence containing no subblock of the form S S reverse(S).
LINKS
Jeffrey Shallit, Experimental Combinatorics on Words Using the Walnut Prover, Talk Presented at Computational Discovery in Mathematics (ACMES 2), University of Western Ontario, May 12 2016
FORMULA
From Colin Barker, May 16 2016: (Start)
a(n) = (1-(-1)^n)/2 for n>8.
a(n) = a(n-2) for n>10.
G.f.: x^2*(1+x^3-x^4)*(1-x^2+x^4) / ((1-x)*(1+x)).
(End)
MATHEMATICA
Join[PadRight[{}, 9, {0, 0, 1}], PadRight[{}, 120, {1, 0}]] (* Harvey P. Dale, Oct 11 2024 *)
PROG
(PARI) concat(vector(2), Vec(x^2*(1+x^3-x^4)*(1-x^2+x^4)/((1-x)*(1+x)) + O(x^50))) \\ Colin Barker, May 16 2016
CROSSREFS
Cf. A241903.
Sequence in context: A072785 A188297 A289128 * A143518 A122414 A288216
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, May 15 2016
STATUS
approved