A090164 Number of configurations of Sam Loyd's sliding block 15-puzzle that require a minimum of n moves to be reached, starting with the empty square at one of the 4 central squares.

1, 4, 10, 20, 38, 80, 174, 372, 762, 1540, 3072, 6196, 12356, 24516, 48179, 94356, 183432, 355330, 682250, 1301874, 2460591, 4617322, 8580175, 15815664, 28854386, 52154316, 93214030

Offset

0,2

Links

Table of n, a(n) for n=0..26.

Maple

See link in A089473.

Prog

(Python) # uses alst(), swap() in A089473
start, shape = "12345-6789ABCDEF", (4, 4)
print(alst(start, shape, maxd=15)) # Michael S. Branicky, Jan 02 2021

Crossrefs

Cf. A087725, A089484, A090165.

Sequence in context: A301178 A279262 A168673 * A261635 A258346 A128640

Adjacent sequences: A090161 A090162 A090163 * A090165 A090166 A090167

Keyword

fini,more,nonn

Author

Hugo Pfoertner, Nov 27 2003

Extensions

a(16)-a(26) from Michael S. Branicky, Dec 28 2020

Status

approved