%I #7 Mar 31 2012 12:35:01
%S 1,16,100,508,3004,18036,110980,692204,4364284,27740164,177454720,
%T 1141017256,7367263276,47731405088,310118484762,2019608005218,
%U 13178042856428,86126612389832,563648913800290,3692893237251226
%N Number of base 16 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