A090035 - OEIS

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A090035

Number of configurations of the 4 X 2 variant of Sam Loyd's sliding block 15-puzzle that require a minimum of n moves to be reached, starting with the empty square in one of the corners.

8

1, 2, 3, 6, 10, 14, 19, 28, 42, 61, 85, 119, 161, 215, 293, 396, 506, 632, 788, 985, 1194, 1414, 1664, 1884, 1999, 1958, 1770, 1463, 1076, 667, 361, 190, 88, 39, 19, 7, 1

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

Data from Karlemo, Östergård. See corresponding link in A087725.

REFERENCES

LINKS

Table of n, a(n) for n=0..36.

Hugo Pfoertner, Solutions of small n*2 sliding block puzzles.

Takaken, n-Puzzle Page.

Takaken, No. 42 (7 puzzles).

EXAMPLE

Starting from

1234

567-

the most distant configuration corresponding to a(36)=1 is

-721

4365

PROG

Program: See link in A089473.

(Python) # alst(), moves(), swap() in A089473

print(alst("-1234567", (4, 2))) # Michael S. Branicky, Dec 30 2020

CROSSREFS

Cf. A087725, A089473. Index of last sequence term: A090033. Other nonsquare sliding block puzzles: A090034, A090036, A090166, A090167.

Sequence in context: A190690 A355509 A084396 * A337611 A325724 A373271

Adjacent sequences: A090032 A090033 A090034 * A090036 A090037 A090038

KEYWORD

fini,full,nonn

AUTHOR

Hugo Pfoertner, Nov 26 2003

STATUS

approved