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Table read by rows: number of partitions of n with k as low median.
26

%I #16 Jul 10 2023 13:08:20

%S 1,1,1,2,0,1,3,1,0,1,4,2,0,0,1,6,3,1,0,0,1,8,4,2,0,0,0,1,11,6,3,1,0,0,

%T 0,1,15,8,4,2,0,0,0,0,1,20,12,5,3,1,0,0,0,0,1,26,16,7,4,2,0,0,0,0,0,1,

%U 35,22,10,5,3,1,0,0,0,0,0,1,45,29,14,6,4,2,0,0,0,0,0,0,1,58,40,19,8,5,3,1

%N Table read by rows: number of partitions of n with k as low median.

%C For a multiset with an odd number of elements, the low median is the same as the median. For a multiset with an even number of elements, the low median is the smaller of the two central elements.

%C Arrange the parts of a partition nonincreasing order. Remove the first part, then the last, then the first remaining part, then the last remaining part, and continue until only a single number, the low median, remains. - _Clark Kimberling_, May 16 2019

%e For the partition [2,1^2], the sole middle element is 1, so that is the low median. For [3,2,1^2], the two middle elements are 1 and 2; the low median is the smaller, 1.

%e First 8 rows:

%e 1

%e 1 1

%e 2 0 1

%e 3 1 0 1

%e 4 2 0 0 1

%e 6 3 1 0 0 1

%e 8 4 2 0 0 0 1

%e 11 6 3 1 0 0 0 1

%e From _Gus Wiseman_, Jul 09 2023: (Start)

%e Row n = 8 counts the following partitions:

%e (71) (62) (53) (44) . . . (8)

%e (611) (521) (431)

%e (5111) (422) (332)

%e (4211) (3221)

%e (41111) (2222)

%e (3311) (22211)

%e (32111)

%e (311111)

%e (221111)

%e (2111111)

%e (11111111)

%e (End)

%t Map[BinCounts[#, {1, #[[1]] + 1, 1}] &[Map[#[[Floor[(Length[#] + 2)/2]]] &, IntegerPartitions[#]]] &, Range[13]] (* _Peter J. C. Moses_, May 14 2019 *)

%Y Row sums are A000041.

%Y Column k = 1 is A027336, ranks A363488.

%Y The high version of this triangle is A124944.

%Y The rank statistic for this triangle is A363941, high version A363942.

%Y A version for mean instead of median is A363945, rank statistic A363943.

%Y A high version for mean instead of median is A363946, rank stat A363944.

%Y A version for mode instead of median is A363952, high A363953.

%Y A008284 counts partitions by length (or decreasing mean), strict A008289.

%Y A325347 counts partitions with integer median, ranks A359908.

%Y A359893 and A359901 count partitions by median.

%Y A360005(n)/2 returns median of prime indices.

%Y Cf. A025065, A026794, A027193, A067538, A237984, A240219, A362608, A363740.

%K nonn,tabl

%O 1,4

%A _Franklin T. Adams-Watters_, Nov 13 2006