A125344 - OEIS

%I #10 Jun 03 2017 15:32:00

%S 1,7,43,247,1527,9497,59245,369803,2308687,14413783,89990323,

%T 561842893,3507795765,21900487967,136732988323,853675514807,

%U 5329817595487,33276057627697,207754954396765,1297092388823683,8098236068810727

%N Number of base 7 circular n-digit numbers with adjacent digits differing by 4 or less.

%C [Empirical] a(base,n)=a(base-1,n)+A025014(n+1) for base>=4.int(n/2)+1.

%F G.f.: (1 - 3*x^2 - 22*x^3 + 3*x^4 + 12*x^5) / ((1 - x - x^2)*(1 - 6*x - 2*x^2 + 3*x^3)) (conjectured). - _Colin Barker_, Jun 03 2017

%o (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>4)+($[(i+1)mod N]`-$[i]`>4))

%K nonn,base

%O 0,2

%A _R. H. Hardin_, Dec 28 2006