login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A240181
Array: t(n,k) is the number of partitions p of n such that the number of distinct numbers in the intersection of p and its conjugate is k, for k >= 0, n >= 1.
4
0, 1, 2, 2, 0, 1, 2, 3, 2, 4, 1, 4, 6, 0, 1, 4, 8, 3, 8, 8, 5, 1, 10, 9, 11, 10, 22, 8, 1, 1, 14, 22, 17, 3, 18, 34, 19, 5, 1, 18, 50, 21, 12, 26, 60, 34, 13, 2, 30, 74, 52, 19, 0, 1, 36, 105, 57, 29, 4, 44, 120, 93, 34, 5, 1, 60, 144, 128, 40, 13, 64, 186
OFFSET
1,3
COMMENTS
First two columns are A240674 and A240675. Sum of numbers in row n is A000041(n), for n >= 1. Number of numbers in row n is A240450(n).
LINKS
EXAMPLE
First 15 rows:
0 ... 1
2
2 ... 0 ... 1
2 ... 3
2 ... 4 ... 1
4 ... 6 ... 0 ...1
4 ... 8 ... 3
8 ... 8 ... 5 ... 1
10 .. 9 ... 11
10 .. 22 .. 8 ... 1 ... 1
14 .. 22 .. 17 .. 3
18 .. 34 .. 19 .. 5 ... 1
18 .. 50 .. 21 .. 12
26 .. 60 .. 34 .. 13 .. 2
30 .. 74 .. 52 .. 19 .. 0 .. 1
In the following table, p and c(p) denote a partition of 6 and its conjugate:
p ........ c(p)
6 ........ 111111
51 ....... 21111
42 ....... 2211
411 ...... 3111
33 ....... 222
321 ...... 321
3111 ..... 411
222 ...... 33
2211 ..... 42
21111 .... 51
111111 ... 6
Let I(p) be number of numbers in the intersection of c and c(p); Then I(p) = 0 for 4 choices of p, I(p) = 1 for 6 choices, I(p) = 2 for 0 choices, and I(p) = 3 for 1 choice. Thus, row 6 is 4 6 0 1.
MATHEMATICA
z = 30; conjugatePartition[part_] := Table[Count[#, _?(# >= i &)], {i, First[#]}] &[part]; c = Map[BinCounts[#, {0, 1 + Max[#]}] &[Map[Length, Map[Intersection[#, conjugatePartition[#]] &, IntegerPartitions[#]]]] &, Range[z]]; Flatten[c] (* this sequence *)
Table[Length[c[[n]]], {n, 1, z}] (* A240450 *) (* Peter J. C. Moses, Apr 10 2014 *)
CROSSREFS
KEYWORD
nonn,easy,tabf
AUTHOR
Clark Kimberling, Apr 12 2014
EXTENSIONS
Name corrected by Clark Kimberling, Sep 28 2023
STATUS
approved