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A246105
Least m > 0 for which (s(m),...,s(n+m-1)) = (s(n),...,s(0)), the reverse of the first n+1 terms of the infinite Fibonacci word A003849.
2
2, 1, 3, 2, 1, 5, 4, 3, 2, 1, 8, 7, 6, 5, 4, 3, 2, 1, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13
OFFSET
0,1
FORMULA
Concatenation of blocks (F(k), F(k - 1), ..., F(3), F(2)) beginning with k = 3, where F = A000045 (Fibonacci numbers).
EXAMPLE
reverse(s(0),...,s(6)) = reverse(0,1,0,0,1,0,1) = (1,0,1,0,0,1,0)
first repeats in A003849 at (s(4),...,s(10)), so that a(6) = 4.
MATHEMATICA
s = Flatten[Nest[{#, #[[1]]} &, {0, 1}, 12]]; b[m_, n_] := b[m, n] = Take[s, {m, n}]; t = -1 + Flatten[Table[Select[Range[2, 1600], b[#, n + # - 1] == Reverse[b[1, n]] &, 1], {n, 1, 120}]]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Aug 14 2014
STATUS
approved