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A316891
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Number of aperiodic integer partitions of n into relatively prime parts whose reciprocal sum is an integer.
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1
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1, 0, 0, 0, 1, 0, 1, 0, 2, 1, 5, 2, 7, 4, 7, 6, 13, 7, 18, 12, 20, 17, 32, 20, 39, 31, 47, 45, 74, 56, 96, 83, 109, 105, 151, 130, 199, 183, 234, 232, 319, 286, 404, 386, 473, 488, 638, 599, 782, 767, 931, 960, 1197, 1165, 1465, 1477, 1747, 1814, 2212, 2196
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OFFSET
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1,9
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COMMENTS
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The reciprocal sum of (y_1, ..., y_k) is 1/y_1 + ... + 1/y_k.
A partition is aperiodic if its multiplicities are relatively prime.
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LINKS
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EXAMPLE
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The a(17) = 13 partitions:
(6443),
(44441),
(3332222), (6322211),
(44222111),
(222222221), (333221111), (632111111),
(4421111111),
(22222211111), (33311111111),
(2222111111111),
(221111111111111).
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MATHEMATICA
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Table[Length[Select[IntegerPartitions[n], And[GCD@@#==1, GCD@@Length/@Split[#]==1, IntegerQ[Sum[1/m, {m, #}]]]&]], {n, 50}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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