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Number of base 17 n-digit numbers with adjacent digits differing by two or less.
3

%I #10 Jul 18 2017 08:01:33

%S 1,17,79,375,1793,8611,41473,200149,967355,4680655,22667487,109848049,

%T 532610303,2583482303,12535495657,60839746967,295338090269,

%U 1433900817213,6962605102325,33811619587041,164207415391765

%N Number of base 17 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.

%F G.f.: (1+7*x-64*x^2+48*x^3+171*x^4-100*x^5-120*x^6+50*x^7+20*x^8-6*x^9) / (1-10*x+27*x^2+4*x^3-73*x^4+19*x^5+50*x^6-14*x^7-8*x^8+2*x^9) (conjectured). - _Colin Barker_, Jul 18 2017

%o (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>2)+($[i+1]`-$[i]`>2))

%Y Cf. Base 17 differing by one or less A126371.

%K nonn,base

%O 1,2

%A _R. H. Hardin_, Dec 28 2006

%E Edited by _Charles R Greathouse IV_, Aug 02 2010