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A286927 Positions of 1 in A286925; complement of A286926. 3
6, 12, 20, 26, 34, 40, 46, 54, 60, 68, 74, 80, 88, 94, 102, 108, 116, 122, 128, 136, 142, 150, 156, 162, 170, 176, 184, 190, 198, 204, 210, 218, 224, 232, 238, 244, 252, 258, 266, 272, 278, 286, 292, 300, 306, 314, 320, 326, 334, 340, 348, 354, 360, 368, 374 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) - a(n-1) is in {6,8} for n>=2, and a(n)/n -> 4 + sqrt(8).

LINKS

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

FORMULA

a(n) = 2*A001952(n).

EXAMPLE

As a word, A286925 = 00000100000100000001..., in which 1 is in positions 6,12,20,26,34,....

MATHEMATICA

s = Nest[Flatten[# /. {0 -> 1, 1 -> {1, 1, 0}}] &, {1}, 11]; (* Sturmian word A080764 *)

w = StringJoin[Map[ToString, s]];

w1 = StringReplace[w, {"0" -> "01", "1" -> "00"}]

st = ToCharacterCode[w1] - 48 ; (* A286925 *)

Flatten[Position[st, 0]];  (* A286926 *)

Flatten[Position[st, 1]];  (* A286927 *)

CROSSREFS

Cf. A080764, A286925, A286926.

Sequence in context: A304391 A145278 A094371 * A189793 A079760 A109895

Adjacent sequences:  A286924 A286925 A286926 * A286928 A286929 A286930

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, May 18 2017

STATUS

approved

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Last modified May 24 17:39 EDT 2019. Contains 323534 sequences. (Running on oeis4.)