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Search: id:A126405
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| A126405 |
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Number of base 18 n-digit numbers with adjacent digits differing by two or less. |
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+0
4
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| 1, 18, 84, 400, 1918, 9236, 44598, 215774, 1045480, 5071280, 24620610, 119613534, 581435182, 2827574694, 13755641338, 66937791112, 325807794512, 1586104016732, 7722649252978, 37605625036546, 183139080847344
(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)+5^(n-1) for base>=2n-1; a(base,n)=a(base-1,n)+5^(n-1)-2 when base=2n-2
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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]`-$[i+1]`>2)+($[i+1]`-$[i]`>2))
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CROSSREFS
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Cf. Base 18 differing by one or less A126372.
Sequence in context: A043961 A067984 A124935 this_sequence A063788 A066854 A059138
Adjacent sequences: A126402 A126403 A126404 this_sequence A126406 A126407 A126408
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KEYWORD
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nonn
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AUTHOR
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Ron Hardin (rhh(AT)cadence.com), Dec 28 2006
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