%I #7 Mar 31 2012 12:35:01
%S 1,15,93,471,2773,16585,101649,631513,3965717,25103901,159916563,
%T 1023792939,6580680769,42436151201,274373773501,1777776831901,
%U 11538964492821,75001583213817,488059829837697,3178929941530215
%N Number of base 15 circular n-digit numbers with adjacent digits differing by 3 or less.
%C [Empirical] a(base,n)=a(base-1,n)+A025012(n+1) for base>=3.int(n/2)+1
%o (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>3)+($[(i+1)mod N]`-$[i]`>3))
%K nonn,base
%O 0,2
%A _R. H. Hardin_, Dec 28 2006