%I #5 Mar 31 2012 12:35:06
%S 1,22,142,938,6246,41790,280454,1886106,12703674,85659918,578078344,
%T 3903599690,26372153784,178228449190,1204818513176,8146123490970,
%U 55086325175168,372549608975494,2519764601804580,17043643041857548
%N Number of base 22 n-digit numbers with adjacent digits differing by three or less.
%C [Empirical] a(base,n)=a(base-1,n)+7^(n-1) for base>=3n-2; a(base,n)=a(base-1,n)+7^(n-1)-2 when base=3n-3
%o (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>3)+($[i+1]`-$[i]`>3))
%Y Cf. Base 22 differing by two or less A126409, one or less A126376.
%K nonn,base
%O 0,2
%A _R. H. Hardin_, Dec 27 2006