cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A285677 {0010->2}-transform of the infinite Fibonacci word A003849.

Original entry on oeis.org

0, 1, 2, 1, 2, 0, 1, 0, 1, 2, 1, 2, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 1, 2, 0, 1, 0, 1, 2, 1, 2, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 1, 2, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 1, 2, 0, 1, 0, 1, 2, 1, 2, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 1, 2, 0, 1, 0, 1, 2, 1, 2, 0, 1, 0, 1, 2
Offset: 1

Views

Author

Clark Kimberling, May 11 2017

Keywords

Comments

As a word, A003849 = 01001010010010100..., and replacing each 0010 by 2 gives 0121201012120101201012120101212010...
Warning: "replacing each 0010 by 2" means "replacing each 0010 by 2 from left to right, consecutively". The result is that the word a(8)...a(14)=0010010 in A003849 is replaced by 201, not by 22. - Michel Dekking, Aug 27 2018

Crossrefs

Programs

  • Mathematica
    s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {0}}] &, {0}, 13] ; (* A003849 *)
    w = StringJoin[Map[ToString, s]]
    w1 = StringReplace[w, {"0010" -> "2"}]
    st = ToCharacterCode[w1] - 48; (* A285677 *)
    Flatten[Position[st, 0]];  (* A285678 *)
    Flatten[Position[st, 1]];  (* A182761 - conjectured *)
    Flatten[Position[st, 2]];  (* A285679 *)

A285679 Positions of 2 in A285677.

Original entry on oeis.org

3, 5, 10, 12, 17, 22, 24, 29, 31, 36, 41, 43, 48, 53, 55, 60, 62, 67, 72, 74, 79, 81, 86, 91, 93, 98, 103, 105, 110, 112, 117, 122, 124, 129, 134, 136, 141, 143, 148, 153, 155, 160, 162, 167, 172, 174, 179, 184, 186, 191, 193, 198, 203, 205, 210, 212, 217
Offset: 1

Views

Author

Clark Kimberling, May 11 2017

Keywords

Comments

A 3-way partition of the positive integers, by positions of 0, 1, 2 in A285677:
A285678: positions of 0; slope t = (4+sqrt(5))/2;
A182761: positions of 1; slope u = (7-sqrt(5))/2;
A285679: positions of 2; slope v = (1+3*sqrt(5))/2;
where 1/t + 1/u + 1/v = 1.
Conjecture: a(n) - a(n-1) is in {2,5} for n>=2.
See A285683 for a proof of this conjecture. - Michel Dekking, Oct 09 2018
a(n) = A285683(n-1) for n>1, see A285683 for a proof. - Michel Dekking, Oct 09 2018

Crossrefs

Programs

  • Mathematica
    s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {0}}] &, {0}, 13] ; (* A003849 *)
    w = StringJoin[Map[ToString, s]]
    w1 = StringReplace[w, {"0010" -> "2"}]
    st = ToCharacterCode[w1] - 48; (* A285677 *)
    Flatten[Position[st, 0]];  (* A285678 *)
    Flatten[Position[st, 1]];  (* A182761 *)
    Flatten[Position[st, 2]];  (* A285679 *)

Formula

a(n) = 3*floor((n-1)*phi) - n + 4
Showing 1-2 of 2 results.