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A371132
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Number of integer partitions of n with fewer distinct parts than distinct divisors of parts.
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5
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0, 0, 1, 1, 2, 3, 5, 6, 10, 14, 21, 28, 40, 53, 73, 96, 130, 170, 223, 288, 375, 480, 616, 780, 990, 1245, 1567, 1954, 2440, 3024, 3745, 4610, 5674, 6947, 8499, 10349, 12591, 15258, 18468, 22277, 26841, 32238, 38673, 46262, 55278, 65881, 78423, 93136, 110477
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OFFSET
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0,5
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COMMENTS
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The Heinz numbers of these partitions are given by A371179.
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LINKS
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EXAMPLE
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The partition (4,3,1,1) has 3 distinct parts {1,3,4} and 4 distinct divisors of parts {1,2,3,4}, so is counted under a(9).
The a(0) = 0 through a(9) = 14 partitions:
. . (2) (3) (4) (5) (6) (7) (8) (9)
(22) (32) (33) (43) (44) (54)
(41) (42) (52) (53) (63)
(222) (61) (62) (72)
(411) (322) (332) (81)
(4111) (422) (333)
(431) (432)
(611) (441)
(2222) (522)
(41111) (621)
(3222)
(4311)
(6111)
(411111)
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MATHEMATICA
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Table[Length[Select[IntegerPartitions[n], Length[Union[#]] < Length[Union@@Divisors/@#]&]], {n, 0, 30}]
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CROSSREFS
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The complement counting all parts on the LHS is A371172, ranks A371165.
These partitions are ranked by A371179.
A008284 counts partitions by length.
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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