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A342529
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Number of compositions of n with distinct first quotients.
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11
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1, 1, 2, 3, 7, 13, 19, 36, 67, 114, 197, 322, 564, 976, 1614, 2729, 4444, 7364, 12357, 20231, 33147
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OFFSET
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0,3
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COMMENTS
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The first quotients of a sequence are defined as if the sequence were an increasing divisor chain, so for example the first quotients of (6,3,1) are (1/2,1/3).
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LINKS
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EXAMPLE
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The composition (2,1,2,3) has first quotients (1/2,2,3/2) so is counted under a(8).
The a(1) = 1 through a(5) = 13 compositions:
(1) (2) (3) (4) (5)
(1,1) (1,2) (1,3) (1,4)
(2,1) (2,2) (2,3)
(3,1) (3,2)
(1,1,2) (4,1)
(1,2,1) (1,1,3)
(2,1,1) (1,2,2)
(1,3,1)
(2,1,2)
(2,2,1)
(3,1,1)
(1,1,2,1)
(1,2,1,1)
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MATHEMATICA
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Table[Length[Select[Join@@Permutations/@IntegerPartitions[n], UnsameQ@@Divide@@@Partition[#, 2, 1]&]], {n, 0, 15}]
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CROSSREFS
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The version for differences instead of quotients is A325545.
The version for equal first quotients is A342495.
The strict unordered version is A342520.
A000005 counts constant compositions.
A000009 counts strictly increasing (or strictly decreasing) compositions.
A000041 counts weakly increasing (or weakly decreasing) compositions.
A167865 counts strict chains of divisors > 1 summing to n.
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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