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A126509
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Number of base 14 n-digit numbers with adjacent digits differing by four or less.
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1
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1, 14, 106, 834, 6626, 52818, 421418, 3363330, 26844922, 214272194, 1710301706, 13651507570, 108965442842, 869755228898, 6942331285450, 55413250676370, 442305075971450, 3530451257562498, 28179839583470762, 224929704767724786
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listen;
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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)+9^(n-1) for base>=4n-3; a(base,n)=a(base-1,n)+9^(n-1)-2 when base=4n-4.
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LINKS
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FORMULA
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G.f.: (1+5*x-16*x^2-30*x^3+14*x^4+20*x^5) / (1-9*x+4*x^2+34*x^3-6*x^4-20*x^5) (conjectured). - Colin Barker, Jul 18 2017
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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]`-$[i+1]`>4)+($[i+1]`-$[i]`>4))
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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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