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A126515
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Number of base 20 n-digit numbers with adjacent digits differing by four or less.
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1
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1, 20, 160, 1320, 11000, 92172, 774696, 6522504, 54969166, 463511924, 3909629218, 32982588380, 278275931230, 2347955939840, 19811499262410, 167167589771462, 1410557938634156, 11902332555068524, 100432557218234836
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refs;
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)+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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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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