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A126492
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Number of base 24 n-digit numbers with adjacent digits differing by three or less.
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3
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1, 24, 156, 1036, 6932, 46592, 314068, 2121404, 14350760, 97189500, 658783572, 4468484736, 30325445672, 205889162656, 1398299571460, 9498979946468, 64541625486340, 438601729211104, 2980942930020288, 20261817487044168
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listen;
history;
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internal format)
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OFFSET
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0,2
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COMMENTS
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[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
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LINKS
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FORMULA
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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
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MAPLE
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b:= proc(n, i) option remember; `if`(n=0, 1, add(
`if`(i=0 or abs(i-j)<4, b(n-1, j), 0), j=1..24))
end:
a:= n-> b(n, 0):
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PROG
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(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>3)+($[i+1]`-$[i]`>3))
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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