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%I #10 Jul 18 2017 08:02:51
%S 1,14,106,834,6626,52818,421418,3363330,26844922,214272194,1710301706,
%T 13651507570,108965442842,869755228898,6942331285450,55413250676370,
%U 442305075971450,3530451257562498,28179839583470762,224929704767724786
%N Number of base 14 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.
%F G.f.: (1+5*x-16*x^2-30*x^3+14*x^4+20*x^5) / (1-9*x+4*x^2+34*x^3-6*x^4-20*x^5) (conjectured). - _Colin Barker_, Jul 18 2017
%o (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>4)+($[i+1]`-$[i]`>4))
%Y Cf. Base 14 differing by three or less A126482, two or less A126401, one or less A126368.
%K nonn,base
%O 0,2
%A _R. H. Hardin_, Dec 28 2006
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