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Number of base 23 n-digit numbers with adjacent digits differing by three or less.
2

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

%S 1,23,149,987,6589,44191,297261,2003755,13527217,91424701,618430417,

%T 4186027957,28348547453,192055244309,1301515597555,8822073211457,

%U 59809085903049,405528485035889,2749918380375081,18648854413662219

%N Number of base 23 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 23 differing by two or less A126410, one or less A126377.

%K nonn,base

%O 0,2

%A _R. H. Hardin_, Dec 27 2006