%I #10 Jul 18 2017 08:05:16
%S 1,16,146,1386,13276,127470,1224594,11766272,113057850,1086341506,
%T 10438376428,100299731078,963754991066,9260480594912,88981641951426,
%U 855002344551114,8215503709753468,78940720623107646,758521643084139202
%N Number of base 16 n-digit numbers with adjacent digits differing by five or less.
%C [Empirical] a(base,n)=a(base-1,n)+11^(n-1) for base>=5n-4; a(base,n)=a(base-1,n)+11^(n-1)-2 when base=5n-5.
%F G.f.: (1+5*x-21*x^2-30*x^3+44*x^4+20*x^5-20*x^6) / (1-11*x+9*x^2+46*x^3-36*x^4-28*x^5+20*x^6) (conjectured). - _Colin Barker_, Jul 18 2017
%o (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>5)+($[i+1]`-$[i]`>5))
%Y Cf. Base 16 differing by four or less A126511, three or less A126484, two or less A126403, one or less A126370.
%K nonn,base
%O 0,2
%A _R. H. Hardin_, Dec 28 2006