%I #10 Aug 13 2012 11:19:16

%S 1,30,88,204,548,1460,4006,11090,31036,87468,248018,706670,2021738,

%T 5804010,16711552,48241364,139572076,404612780,1175026834,3417771710,

%U 9955368238,29035695998,84784671532,247838482400,725183659570

%N Number of base 30 circular n-digit numbers with adjacent digits differing by 1 or less.

%C [Empirical] a(base,n)=a(base-1,n)+A002426(n+1) for base>=1.int(n/2)+1

%C a(n) = T(n, 30) where T(n, k) = Sum_{j=1..k} (1+2*cos(j*Pi/(k+1)))^n. These are the number of smooth cyclic words of length n over the alphabet {1,2,..,30}. See theorem 3.3 in Knopfmacher and others, reference in A124696. - _Peter Luschny_, Aug 13 2012

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

%K nonn,base

%O 0,2

%A _R. H. Hardin_, Dec 28 2006