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Search: id:A126502
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| A126502 |
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Number of base 7 n-digit numbers with adjacent digits differing by four or less. |
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+0
2
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| 1, 7, 43, 269, 1679, 10483, 65449, 408623, 2551187, 15928021, 99444631, 620870267, 3876326801, 24201367447, 151098247483, 943363239389, 5889771828959, 36772062710083, 229581830200249, 1433365791134783
(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)+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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PROGRAM
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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 7 differing by three or less A126475, two or less A126394, one or less A126361.
Sequence in context: A003464 A022036 A015451 this_sequence A042213 A164775 A127999
Adjacent sequences: A126499 A126500 A126501 this_sequence A126503 A126504 A126505
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KEYWORD
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nonn
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AUTHOR
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Ron Hardin (rhhardin(AT)att.net), Dec 28 2006
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