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Search: id:A126488
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| A126488 |
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Number of base 20 n-digit numbers with adjacent digits differing by three or less. |
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+0
3
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| 1, 20, 128, 840, 5560, 36988, 246840, 1650808, 11056590, 74130748, 497387482, 3339002940, 22423219250, 150623072388, 1011962290858, 6799752144942, 45694220498130, 307084056184964, 2063824981953422, 13870824556736138
(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)+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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PROGRAM
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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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Cf. Base 20 differing by two or less A126407, one or less A126374.
Sequence in context: A004634 A073968 A125330 this_sequence A005551 A006417 A156392
Adjacent sequences: A126485 A126486 A126487 this_sequence A126489 A126490 A126491
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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 27 2006
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