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A126507
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Number of base 12 n-digit numbers with adjacent digits differing by four or less.
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1
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1, 12, 88, 672, 5168, 39796, 306520, 2361008, 18186104, 140082072, 1079010248, 8311293248, 64019406944, 493122351856, 3798374049312, 29257739717488, 225363621979872, 1735908604096736, 13371185000068864, 102994240528644064
(list;
graph;
refs;
listen;
history;
text;
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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Table of n, a(n) for n=0..19.
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FORMULA
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G.f.: (1+4*x-8*x^2-14*x^3+6*x^4+6*x^5) / (1-8*x+18*x^3-2*x^4-6*x^5) (conjectured). - Colin Barker, Jul 17 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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Cf. Base 12 differing by three or less A126480, two or less A126399, one or less A126366.
Sequence in context: A164608 A081009 A155635 * A181704 A009657 A012088
Adjacent sequences: A126504 A126505 A126506 * A126508 A126509 A126510
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KEYWORD
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nonn,base
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AUTHOR
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R. H. Hardin, Dec 28 2006
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STATUS
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approved
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