Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #7 Mar 31 2012 12:35:06
%S 1,30,250,2130,18290,157782,1365186,11836674,102784246,893546734,
%T 7774696328,67691981738,589674316476,5138751184130,44795493135264,
%U 390582096696514,3406186539096420,29708773287301186,259147729207407892
%N Number of base 30 n-digit numbers with adjacent digits differing by four or less.
%C [Empirical] a(base,n)=a(base-1,n)+9^(n-1) for base>=4n-3; a(base,n)=a(base-1,n)+9^(n-1)-2 when base=4n-4
%o (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>4)+($[i+1]`-$[i]`>4))
%Y Cf. Base 30 differing by three or less A126498, two or less A126417, one or less A126384.
%K nonn,base
%O 0,2
%A _R. H. Hardin_, Dec 28 2006