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A124944
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Table, number of partitions of n with k as high median.
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23
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1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 1, 1, 4, 3, 1, 1, 1, 1, 6, 4, 1, 1, 1, 1, 1, 8, 6, 3, 1, 1, 1, 1, 1, 11, 8, 5, 1, 1, 1, 1, 1, 1, 15, 11, 7, 3, 1, 1, 1, 1, 1, 1, 20, 15, 9, 5, 1, 1, 1, 1, 1, 1, 1, 26, 21, 12, 8, 3, 1, 1, 1, 1, 1, 1, 1, 35, 27, 16, 10, 5, 1, 1, 1, 1, 1, 1, 1, 1, 45, 37, 21, 13, 8, 3
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OFFSET
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1,7
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COMMENTS
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For a multiset with an odd number of elements, the high median is the same as the median. For a multiset with an even number of elements, the high median is the larger of the two central elements.
This table may be read as an upper right triangle with n >= 1 as column index and k >= 1 as row index. - Peter Munn, Jul 16 2017
Arrange the parts of a partition nonincreasing order. Remove the last part, then the first, then the last remaining part, then the first remaining part, and continue until only a single number, the high median, remains. - Clark Kimberling, May 14 2019
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LINKS
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EXAMPLE
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For the partition [2,1^2], the sole middle element is 1, so that is the high median. For [3,2,1^2], the two middle elements are 1 and 2; the high median is the larger, 2.
Triangle begins:
1
1 1
1 1 1
2 1 1 1
3 1 1 1 1
4 3 1 1 1 1
6 4 1 1 1 1 1
8 6 3 1 1 1 1 1
11 8 5 1 1 1 1 1 1
15 11 7 3 1 1 1 1 1 1
20 15 9 5 1 1 1 1 1 1 1
26 21 12 8 3 1 1 1 1 1 1 1
35 27 16 10 5 1 1 1 1 1 1 1 1
45 37 21 13 8 3 1 1 1 1 1 1 1 1
58 48 29 16 11 5 1 1 1 1 1 1 1 1 1
Row n = 8 counts the following partitions:
(611) (521) (431) (44) (53) (62) (71) (8)
(5111) (422) (332)
(41111) (4211) (3311)
(32111) (3221)
(311111) (2222)
(221111) (22211)
(2111111)
(11111111)
(End)
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MATHEMATICA
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Map[BinCounts[#, {1, #[[1]] + 1, 1}] &[Map[#[[Floor[(Length[#] + 1)/2]]] &, IntegerPartitions[#]]] &, Range[13]] (* Peter J. C. Moses, May 14 2019 *)
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CROSSREFS
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The low version of this triangle is A124943.
A008284 counts partitions by length, maximum, or decreasing mean.
A360005(n)/2 returns median of prime indices.
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KEYWORD
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AUTHOR
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STATUS
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approved
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