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Search: id:A081732
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| A081732 |
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Number of numbers that differ from n in ternary representation by exactly one edit-operation: deletion, insertion, or substitution. |
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+0
1
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| 4, 6, 6, 11, 10, 11, 11, 11, 10, 14, 15, 15, 15, 14, 15, 16, 16, 15, 14, 15, 15, 16, 15, 16, 15, 15, 14, 18, 19, 19, 20, 19, 20, 20, 20, 19, 19, 20, 20, 19, 18, 19, 20, 20, 19, 20, 21, 21, 21, 20, 21, 20, 20, 19, 18, 19, 19, 20, 19, 20, 20, 20, 19, 20, 21, 21, 20, 19, 20, 21
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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a(n) = #{j: LD-3(n,j)=1}, where LD-3 is the Levenshtein distance on ternary strings.
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LINKS
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Michael Gilleland, Levenshtein Distance. [It has been suggested that this algorithm gives incorrect results sometimes. - njas]
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EXAMPLE
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n=12: ternary representation of numbers at Levenshtein distance 1 from 12='110':
{10, 11, 100, 111, 112, 120, 210, 1010, 1100, 1101,
1102, 1110, 1120, 1210, 2110}, therefore a(12)=15.
n=42: ternary representation of numbers at Levenshtein distance 1 from 42='1120':
{110, 112, 120, 1020, 1100, 1110, 1121, 1122, 1220,
2120, 10120, 11020, 11120, 11200, 11201, 11202, 11210, 11220, 12120, 21120},
therefore a(42)=20.
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CROSSREFS
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Cf. A080950, A080910, A007089.
Adjacent sequences: A081729 A081730 A081731 this_sequence A081733 A081734 A081735
Sequence in context: A058640 A075653 A075656 this_sequence A079033 A077038 A053320
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KEYWORD
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nonn,base
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 06 2003
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