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Search: id:A126374
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| A126374 |
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Number of base 20 n-digit numbers with adjacent digits differing by one or less. |
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+0
5
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| 1, 20, 58, 170, 500, 1474, 4352, 12864, 38058, 112674, 333776, 989236, 2933102, 8699864, 25812862, 76609418, 227424420, 675289026, 2005535520, 5957318820, 17698806798, 52590044172, 156287402420, 464515721050, 1380792800096
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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[Empirical] a(base,n)=a(base-1,n)+3^(n-1) for base>=n; a(base,n)=a(base-1,n)+3^(n-1)-2 when base=n-1
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PROGRAM
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(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>1)+($[i+1]`-$[i]`>1))
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CROSSREFS
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Sequence in context: A104100 A069132 A124713 this_sequence A163761 A154072 A078184
Adjacent sequences: A126371 A126372 A126373 this_sequence A126375 A126376 A126377
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KEYWORD
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nonn,base
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AUTHOR
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Ron Hardin (rhhardin(AT)att.net), Dec 26 2006
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