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A288174 Positions of 0 in A288173; complement of A288175. 3
1, 2, 4, 5, 6, 8, 9, 11, 12, 13, 14, 16, 17, 19, 20, 21, 23, 24, 26, 27, 28, 30, 31, 32, 34, 35, 37, 38, 39, 41, 42, 44, 45, 46, 47, 49, 50, 52, 53, 54, 56, 57, 59, 60, 61, 62, 64, 65, 67, 68, 69, 70, 72, 73, 75, 76, 77, 79, 80, 82, 83, 84, 85, 87, 88, 90 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Conjecture: lim_{n->infinity} a(n)/n = 1.36..., and if m denotes this number, then -1 < m - a(n)/n < 1 for n >= 1.

From Michel Dekking, Feb 23 2020: (Start)

Proof of the first part of this conjecture.

Let a(0):=0. We write this sequence as the sum of its first differences:

a(n) = Sum_{k=0..n-1} a(k+1)-a(k).

We know (see A288173) that A288173 can be generated as a decoration delta(t) of the fixed point t of the morphism alpha given by

alpha(A) = AB, alpha(B) = AC, alpha(C) = ABB.

Here delta is the morphism

delta(A) = 001, delta(B) = 0001, delta(C) = 00001.

Let e = A288175 be the sequence of positions of 1 in A288173. Note that if we are at the n-th 1, then we have seen e(n)-n zeros. So the position of the (e(n)-n)-th zero is e(n)-1.

Let m(n):=e(n)-n. Then

a(m(n))/m(n) = (e(n)-1)/m(n) = (e(n)-1)/n * n/(e(n)-n).

According to the comments at e = A288175, the first factor in this product converges to 3.7092753596..., and the second to 1/(3.7092753596... - 1).

It follows that as n->infinity,

a(m(n))/m(n) -> 1.36900369004... .

It is easy to see from this that the whole sequence converges, and so

a(n)/n -> 1.36900369004... . (End)

LINKS

Clark Kimberling, Table of n, a(n) for n = 1..10000

MATHEMATICA

s = {0, 0}; w[0] = StringJoin[Map[ToString, s]];

w[n_] := StringReplace[w[n - 1], {"00" -> "0010", "1" -> "001"}]

Table[w[n], {n, 0, 8}]

st = ToCharacterCode[w[11]] - 48 (* A288173 *)

Flatten[Position[st, 0]] (* A288174 *)

Flatten[Position[st, 1]] (* A288175 *)

CROSSREFS

Cf. A288173, A288175.

Sequence in context: A171599 A328594 A346129 * A280998 A043687 A087118

Adjacent sequences: A288171 A288172 A288173 * A288175 A288176 A288177

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Jun 07 2017

STATUS

approved

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Last modified March 31 21:40 EDT 2023. Contains 361673 sequences. (Running on oeis4.)