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A126492 Number of base 24 n-digit numbers with adjacent digits differing by three or less.

%I A126492 #8 Sep 25 2015 11:40:55
%S A126492 1,24,156,1036,6932,46592,314068,2121404,14350760,97189500,658783572,
%T A126492 4468484736,30325445672,205889162656,1398299571460,9498979946468,
%U A126492 64541625486340,438601729211104,2980942930020288,20261817487044168
%N A126492 Number of base 24 n-digit numbers with adjacent digits differing by three or less.
%C A126492 [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
%H A126492 Alois P. Heinz, <a href="/A126492/b126492.txt">Table of n, a(n) for n = 0..1000</a>
%F A126492 G.f.: -(36*x^11 -104*x^10 -272*x^9 +557*x^8 +624*x^7 -998*x^6 -524*x^5 +660*x^4 +134*x^3 -127*x^2 +10*x +1) / (12*x^11 -40*x^10 -80*x^9 +223*x^8 +156*x^7 -410*x^6 -88*x^5 +276*x^4 -10*x^3 -53*x^2 +14*x -1). - _Alois P. Heinz_, Sep 25 2015
%p A126492 b:= proc(n, i) option remember; `if`(n=0, 1, add(
%p A126492      `if`(i=0 or abs(i-j)<4, b(n-1, j), 0), j=1..24))
%p A126492     end:
%p A126492 a:= n-> b(n, 0):
%p A126492 seq(a(n), n=0..20);  # _Alois P. Heinz_, Sep 25 2015
%o A126492 (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 A126492 Cf. Base 24 differing by two or less A126411, one or less A126378.
%K A126492 nonn,base
%O A126492 0,2
%A A126492 _R. H. Hardin_, Dec 27 2006