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Search: id:A088177
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| A088177 |
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a(1)=1, a(2)=1; for n>2, a(n) is the smallest positive integer such that the products a(i)*a(i+1), i=1..n-1, are all distinct. |
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+0
2
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| 1, 1, 2, 2, 3, 1, 5, 2, 4, 3, 3, 5, 4, 4, 6, 3, 7, 1, 11, 2, 7, 4, 8, 5, 5, 6, 6, 7, 5, 9, 3, 11, 4, 12, 5, 10, 7, 7, 8, 8, 9, 6, 11, 5, 13, 1, 17, 2, 13, 3, 17, 4, 13, 6, 14, 7, 9, 9, 10, 8, 11, 7, 13, 8, 12, 9, 11, 10, 10, 12, 11, 11, 13, 9, 14, 8, 16, 9, 15, 5, 17, 6, 19, 1, 23, 2, 19, 3, 23, 4, 19
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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A088178 is the sequence of distinct products a(i)a(i+1), i=1,2,3,... and appears to be a permutation of the natural numbers.
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EXAMPLE
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Given that the sequence begins 1,1,2,2,... then a(5)=3, since either of the choices a(5)=1 or a(5)=2 would lead to a repetition of one of the previous products 1,2,4 of adjacent pairs of terms.
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CROSSREFS
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Cf. A088178.
Sequence in context: A141197 A035207 A071281 this_sequence A028507 A096226 A155980
Adjacent sequences: A088174 A088175 A088176 this_sequence A088178 A088179 A088180
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KEYWORD
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nonn
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AUTHOR
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John W. Layman (layman(AT)math.vt.edu), Sep 22 2003
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