OFFSET
1,2
FORMULA
EXAMPLE
For n = 5, the initial configuration 01102 (with the top of the deck to the left) requires 9 moves to reach an already visited configuration: 01102 -> 11020 -> 10120 -> 01210 -> 12100 -> 21010 -> 12010 -> 20101 -> 02101 -> 21010. This is the maximum for 5 cards, so a(5) = 9.
Lexicographically first optimal initial configuration for 1 <= n <= 14:
n a(n) configuration
1 1 0
2 2 01
3 3 001
4 6 0012
5 9 01102
6 13 010012
7 20 0111023
8 30 01232213
9 46 012110234
10 74 0111234234
11 106 01112343324
12 152 011102345345
13 242 0122112345345
14 318 01112345326546
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Pontus von Brömssen, Feb 04 2023
STATUS
approved