A335597 Length of shortest string having n distinct letters and containing no 4-antipowers.

1, 2, 3, 5, 6, 10, 16, 52

Offset

1,2

Comments

A 4-antipower consists of 4 consecutive blocks of the same length that are pairwise distinct. For example, 01021210 = (01)(02)(12)(10) is a 4-antipower.

Links

Table of n, a(n) for n=1..8.

Example

Here are the lexicographically least examples for 1 <= n <= 8:
1: 0
2: 01
3: 012
4: 01123
5: 012234
6: 0121213345
7: 0112333333334456
8: 0112333333333333333333333333333333333334333333335567

Crossrefs

Cf. A275061.

Sequence in context: A018727 A161715 A347799 * A164523 A227305 A326612

Adjacent sequences: A335594 A335595 A335596 * A335598 A335599 A335600

Keyword

nonn,more

Author

Jeffrey Shallit, Jun 14 2020

Status

approved