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A089483
Number of configurations of the sliding block 8-puzzle that require a minimum of n moves to be reached, starting with the empty square at mid-side.
3
1, 3, 5, 10, 14, 28, 42, 80, 108, 202, 278, 524, 726, 1348, 1804, 3283, 4193, 7322, 8596, 13930, 14713, 21721, 19827, 25132, 18197, 18978, 9929, 7359, 2081, 878, 126, 2
OFFSET
0,2
REFERENCES
See A087725.
EXAMPLE
Starting with
1-2
345
678
the two final configurations requiring 31 moves are
86- ... -86
547 and 743
231 ... 251
MAPLE
See link in A089473.
PROG
(Python) # alst(), moves(), swap() in A089473
print(alst("1-2345678", (3, 3))) # Michael S. Branicky, Dec 30 2020
CROSSREFS
KEYWORD
fini,full,nonn
AUTHOR
Hugo Pfoertner, Nov 19 2003
STATUS
approved