A126385 - OEIS

%I #5 Mar 31 2012 12:35:05

%S 1,31,91,269,797,2365,7025,20883,62115,184845,550289,1638775,4881719,

%T 14545715,43350415,129222077,385262397,1148802957,3426077313,

%U 10218944199,30483682935,90944672583,271351287651,809707376697

%N Number of base 31 n-digit numbers with adjacent digits differing by one or less.

%C [Empirical] a(base,n)=a(base-1,n)+3^(n-1) for base>=n; a(base,n)=a(base-1,n)+3^(n-1)-2 when base=n-1

%o (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>1)+($[i+1]`-$[i]`>1))

%K nonn,base

%O 0,2

%A _R. H. Hardin_, Dec 26 2006