login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A151943 Maximal number of moves required for the 2 X n generalization of the sliding block 15-puzzle (or fifteen-puzzle). 2
1, 6, 21, 36, 55, 80, 108, 140 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See A087725 for more about this problem and its history. See also A151944.

Three corrections to table III of the Korf reference: the radius of the 2x4 should be 36; the depth of the 3x5 should be 52, and the ratio of the 3x5 should be 14.379. [Tomas Rokicki, Aug 17 2011]

REFERENCES

Richard Korf, Linear-time Disk-Based Implicit Graph Search, Journal of the ACM 55 (2008), No. 6

LINKS

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

Anton Kulchitsky, Comments on the Fifteen Puzzle

Tomas Rokicki, Comments on Twenty-Four puzzle, some observations

CROSSREFS

Sequence in context: A139606 A047717 A089982 * A207339 A284988 A056488

Adjacent sequences:  A151940 A151941 A151942 * A151944 A151945 A151946

KEYWORD

nonn,hard,more

AUTHOR

Anton Kulchitsky (kulchits(AT)arsc.edu), Aug 14 2009, Aug 16 2009

EXTENSIONS

Extended the sequence for 2x7 and 2x8 from Table III of Richard Korf's work.

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 14 01:24 EST 2019. Contains 329108 sequences. (Running on oeis4.)