A126418 - OEIS

%I #5 Mar 31 2012 12:35:06

%S 1,31,149,725,3543,17361,85223,418899,2061105,10149405,50011235,

%T 246566635,1216199805,6001382075,29624479933,146279954561,

%U 722500541847,3569422111283,17638150070523,87175432519409,430936179702041

%N Number of base 31 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 31 differing by one or less A126385.

%K nonn,base

%O 0,2

%A _R. H. Hardin_, Dec 28 2006