%I A090164
%S A090164 1,4,10,20,38,80,174,372,762,1540,3072,6196,12356,24516,48179,94356
%N 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.
%p A090164 See link in A089473.
%Y A090164 Cf. A087725, A089484, A090165.
%Y A090164 Sequence in context: A008058 A038420 A008254 this_sequence A128640 A128641 
               A164617
%Y A090164 Adjacent sequences: A090161 A090162 A090163 this_sequence A090165 A090166 
               A090167
%K A090164 fini,more,nonn
%O A090164 0,2
%A A090164 Hugo Pfoertner (hugo(AT)pfoertner.org), Nov 27 2003