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A089484 Number of configurations of the sliding block 15-puzzle that require a minimum of n moves to be reached, starting with the empty square in one of the corners. 11
1, 2, 4, 10, 24, 54, 107, 212, 446, 946, 1948, 3938, 7808, 15544, 30821, 60842, 119000, 231844, 447342, 859744, 1637383, 3098270, 5802411, 10783780, 19826318, 36142146, 65135623, 116238056, 204900019, 357071928, 613926161, 1042022040 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The last sequence term is a(80). The total number of possible configurations of an m*m sliding block puzzle is (m*m)!/2=A088020(4)/2, therefore Sum_i (i=0..80) a(i)=16!/2=10461394944000.

REFERENCES

See A087725.

LINKS

Herman Jamke, Table of n, a(n) for n = 0..80 (complete sequence)

Herbert Kociemba, 15-Puzzle Optimal Solver

R. E. Korf and P. Schultze, Large-Scale Parallel Breadth-First Search

Hugo Pfoertner, Configuration counts for n*n sliding block puzzles.

CROSSREFS

Cf. A087725, A089473, A090031, A090032, A090164, A090165, A088020.

Sequence in context: A094837 A136427 A018114 * A132732 A275447 A095214

Adjacent sequences:  A089481 A089482 A089483 * A089485 A089486 A089487

KEYWORD

fini,full,nonn

AUTHOR

Hugo Pfoertner, Nov 25 2003

EXTENSIONS

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Oct 19 2006

STATUS

approved

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Last modified March 29 13:17 EDT 2017. Contains 284270 sequences.