login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A333325 Lexicographically earliest sequence over {0,1,2} that has the shortest square subsequence. 2
0, 1, 0, 2, 0, 1, 0, 0, 1, 2, 0, 1, 0, 2, 0, 1, 2, 0, 2, 1, 0, 1, 2, 0, 1, 0, 2, 0, 1, 2, 0, 2, 2, 0, 1, 0, 2, 0, 1, 2, 0, 0, 1, 0, 2, 0, 1, 0, 0, 1, 2, 0, 1, 0, 2, 0, 1, 2, 0, 2, 1, 0, 1, 2, 0, 1, 0, 2, 0, 1, 2, 0, 2, 2, 0, 1, 0, 2, 0, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

This is very similar to A333307.  See that sequence for details about the precise definition. - N. J. A. Sloane, Nov 29 2020

LINKS

Table of n, a(n) for n=0..80.

EXAMPLE

a(7) = 0, since:

0 yields a square subsequence of length 2: [0, 0],

1 of length 4: [0, 1, 0, 1],

2 of length 8: [0, 1, 0, 2, 0, 1, 0, 2].

PROG

(Python)

def a333325(n):

  seq = []

  for k in range(n):

    options = []

    l = len(seq) + 1

    for m in range(3): # base

      for i in range(l // 2, -1, -1):

        if seq[l - 2 * i: l - i] == seq[l - i:] + [m]: break

      options.append(2 * i)

    seq.append(options.index(min(options)))

  return seq

print(a333325(81))

CROSSREFS

Cf. A006345, A157238, A283131, A007814.

Sequence in context: A171774 A002324 A101671 * A078979 A063974 A144628

Adjacent sequences:  A333322 A333323 A333324 * A333326 A333327 A333328

KEYWORD

nonn

AUTHOR

Jan Koornstra, Mar 15 2020

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 24 00:14 EDT 2021. Contains 345403 sequences. (Running on oeis4.)