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 A090575 #10 Dec 29 2020 06:32:21 %S A090575 1,5,17,52,164,496,1608,5008,16024,48732,153564,460984,1437632, %T A090575 4263236,13150544,38498798,117497284 %N A090575 Number of configurations of the 3-dimensional 3 X 3 X 3 sliding cube puzzle that require a minimum of n moves to be reached, starting with the empty space at the center of one of the 6 faces of the combination cube. %C A090575 See A090573. %e A090575 a(1)=5 because the empty space located at the center of a face of the combination cube in the assumed initial configuration can be replaced in the first move by either the cube from the center of the combination cube or by one of the 4 adjacent cubes located at the edges of the face initially containing the empty space. %o A090575 (Python) # uses alst(), swap() in A089473, moves3d() in A090573 %o A090575 moves = lambda p, shape: moves3d(p, shape) %o A090575 start, shape = "1234-56789ABCDEFGHIJKLMNOPQ", (3, 3, 3) %o A090575 print(alst(start, shape, maxd=12)) # _Michael S. Branicky_, Dec 28 2020 %Y A090575 A090572 2 X 2 X 2 puzzle, A090573, A090574, A090576 3 X 3 X 3 puzzle with different initial configurations. %K A090575 fini,hard,more,nonn %O A090575 0,2 %A A090575 _Hugo Pfoertner_, Jan 15 2004 %E A090575 a(13)-a(16) from _Michael S. Branicky_, Dec 28 2020