This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A089483 #6 Dec 31 2020 02:12:29
%S A089483 1,3,5,10,14,28,42,80,108,202,278,524,726,1348,1804,3283,4193,7322,
%T A089483 8596,13930,14713,21721,19827,25132,18197,18978,9929,7359,2081,878,
%U A089483 126,2
%N 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.
%D A089483 See A087725.
%H A089483 Hugo Pfoertner, <a href="http://www.randomwalk.de/sequences/sbpuzz33.txt">Table of solution lengths of the 8-puzzle</a>
%e A089483 Starting with
%e A089483 1-2
%e A089483 345
%e A089483 678
%e A089483 the two final configurations requiring 31 moves are
%e A089483 86- ... -86
%e A089483 547 and 743
%e A089483 231 ... 251
%p A089483 See link in A089473.
%o A089483 (Python) # alst(), moves(), swap() in A089473
%o A089483 print(alst("1-2345678", (3, 3))) # _Michael S. Branicky_, Dec 30 2020
%Y A089483 Cf. A089473, A089474, A089484, A087725, A090031.
%K A089483 fini,full,nonn
%O A089483 0,2
%A A089483 _Hugo Pfoertner_, Nov 19 2003