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%I #5 Mar 31 2012 12:35:06
%S 1,27,177,1183,7961,53795,364489,2474351,16821389,114483903,779844261,
%T 5315901159,36257137597,247407046293,1688869025869,11532291728235,
%U 78767464674013,538108605910885,3676788059570219,25126354998525521
%N Number of base 27 n-digit numbers with adjacent digits differing by three or less.
%C [Empirical] a(base,n)=a(base-1,n)+7^(n-1) for base>=3n-2; a(base,n)=a(base-1,n)+7^(n-1)-2 when base=3n-3
%o (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>3)+($[i+1]`-$[i]`>3))
%Y Cf. Base 27 differing by two or less A126414, one or less A126381.
%K nonn,base
%O 0,2
%A _R. H. Hardin_, Dec 27 2006