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Number of base 11 n-digit numbers with adjacent digits differing by five or less.
1

%I #13 Jul 18 2017 01:46:34

%S 1,11,91,781,6691,57343,491429,4211559,36093157,309319197,2650872719,

%T 22718040927,194694139719,1668533310731,14299369323775,

%U 122545928057115,1050221456858969,9000422339067177,77133829015319501

%N Number of base 11 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.

%F G.f.: (1+3*x-3*x^2-4*x^3+x^4+x^5) / ((1+x)*(1-9*x+3*x^2+6*x^3-x^4-x^5)) (conjectured). - _Colin Barker_, Jul 17 2017

%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 11 differing by four or less A126506, three or less A126479, two or less A126398, one or less A126365.

%K nonn,base

%O 0,2

%A _R. H. Hardin_, Dec 28 2006