%I #5 Mar 31 2012 12:35:05
%S 1,25,119,575,2793,13611,66473,325149,1592355,7805655,38292485,
%T 187972885,923231055,4536538325,22300261185,109658861091,539395083843,
%U 2653895007787,13060517277349,64287300999691,316495856518423
%N Number of base 25 n-digit numbers with adjacent digits differing by two or less.
%C [Empirical] a(base,n)=a(base-1,n)+5^(n-1) for base>=2n-1; a(base,n)=a(base-1,n)+5^(n-1)-2 when base=2n-2
%o (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>2)+($[i+1]`-$[i]`>2))
%Y Cf. Base 25 differing by one or less A126379.
%K nonn,base
%O 0,2
%A _R. H. Hardin_, Dec 28 2006