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Number of base 20 n-digit numbers with adjacent digits differing by five or less.
0

%I #7 Mar 31 2012 12:35:06

%S 1,20,190,1870,18600,185922,1862204,18667904,187205534,1877615174,

%T 18833087302,188906865160,1894866747430,19006912484080,

%U 190653725780160,1912402757442222,19182869344924714,192418948095124214

%N Number of base 20 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

%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 20 differing by four or less A126515, three or less A126488, two or less A126407, one or less A126374.

%K nonn,base

%O 0,2

%A _R. H. Hardin_, Dec 28 2006