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A296508
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Irregular triangle read by rows: T(n,k) is the size of the subpart that is adjacent to the k-th peak of the largest Dyck path of the symmetric representation of sigma(n), or T(n,k) = 0 if the mentioned subpart is already associated to a previous peak or if there is no subpart adjacent to the k-th peak, with n >= 1, k >= 1.
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43
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1, 3, 2, 2, 7, 0, 3, 3, 11, 1, 0, 4, 0, 4, 15, 0, 0, 5, 3, 5, 9, 0, 9, 0, 6, 0, 0, 6, 23, 5, 0, 0, 7, 0, 0, 7, 12, 0, 12, 0, 8, 7, 1, 0, 8, 31, 0, 0, 0, 0, 9, 0, 0, 0, 9, 35, 2, 0, 2, 0, 10, 0, 0, 0, 10, 39, 0, 3, 0, 0, 11, 5, 0, 5, 0, 11, 18, 0, 0, 0, 18, 0, 12, 0, 0, 0, 0, 12, 47, 13, 0, 0, 0, 0, 13, 0, 5, 0, 0, 13
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OFFSET
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1,2
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COMMENTS
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Conjecture: row n is formed by the odd-indexed terms of the n-th row of triangle A280850 together with the even-indexed terms of the same row but listed in reverse order. Examples: the 15th row of A280850 is [8, 8, 7, 0, 1] so the 15th row of this triangle is [8, 7, 1, 0, 8]. The 75th row of A280850 is [38, 38, 21, 0, 3, 3, 0, 0, 0, 21, 0] so the 75h row of this triangle is [38, 21, 3, 0, 0, 0, 21, 0, 3, 0, 38].
For the definition of "subparts" see A279387.
For more information about the mentioned Dyck paths see A237593.
T(n,k) could be called the "charge" of the k-th peak of the largest Dyck path of the symmetric representation of sigma(n).
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LINKS
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EXAMPLE
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Triangle begins (rows 1..28):
1;
3;
2, 2;
7, 0;
3, 3;
11, 1, 0;
4, 0, 4;
15, 0, 0;
5, 3, 5;
9, 0, 9, 0;
6, 0, 0, 6;
23, 5, 0, 0;
7, 0, 0, 7;
12, 0, 12, 0;
8, 7, 1, 0, 8;
31, 0, 0, 0, 0;
9, 0, 0, 0, 9;
35, 2, 0, 2, 0;
10, 0, 0, 0, 10;
39, 0, 3, 0, 0;
11, 5, 0, 5, 0, 11;
18, 0, 0, 0, 18, 0;
12, 0, 0, 0, 0, 12;
47, 13, 0, 0, 0, 0;
13, 0, 5, 0, 0, 13;
21, 0, 0, 0 21, 0;
14, 6, 0, 6, 0, 14;
55, 0, 0, 1, 0, 0, 0;
...
For n = 15 we have that the 14th row of triangle A237593 is [8, 3, 1, 2, 2, 1, 3, 8] and the 15th row of the same triangle is [8, 3, 2, 1, 1, 1, 1, 2, 3, 8], so the diagram of the symmetric representation of sigma(15) is constructed in the third quadrant as shown below in Figure 1:
. _ _
. | | | |
. | | | |
. | | | |
. 8 | | | |
. | | | |
. | | | |
. | | | |
. |_|_ _ _ |_|_ _ _
. | |_ _ 8 | |_ _
. |_ | |_ _ |
. |_ |_ 7 |_| |_
. 8 |_ _| 1 |_ _|
. | 0 |
. |_ _ _ _ _ _ _ _ |_ _ _ _ _ _ _ _
. |_ _ _ _ _ _ _ _| |_ _ _ _ _ _ _ _|
. 8 8
.
. Figure 1. The symmetric Figure 2. After the dissection
. representation of sigma(15) of the symmetric representation
. has three parts of size 8 of sigma(15) into layers of
. because every part contains width 1 we can see four subparts,
. 8 cells, so the 15th row of so the 15th row of this triangle is
. triangle A237270 is [8, 8, 8]. [8, 7, 1, 0, 8]. See also below.
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Illustration of first 50 terms (rows 1..16 of triangle) in an irregular spiral which can be find in the top view of the pyramid described in A244050:
.
. 12 _ _ _ _ _ _ _ _
. | _ _ _ _ _ _ _|_ _ _ _ _ _ _ 7
. | | |_ _ _ _ _ _ _|
. 0 _| | |
. |_ _|9 _ _ _ _ _ _ |_ _ 0
. 12 _ _| | _ _ _ _ _|_ _ _ _ _ 5 |_ 0
. 0 _ _ _| | 0 _| | |_ _ _ _ _| |
. | _ _ _| 9 _|_ _| |_ _ 3 |_ _ _ 7
. | | 0 _ _| | 11 _ _ _ _ |_ | | |
. | | | _ _| 1 _| _ _ _|_ _ _ 3 |_|_ _ 5 | |
. | | | | 0 _|_| | |_ _ _| | | | |
. | | | | | _ _| |_ _ 3 | | | |
. | | | | | | 3 _ _ | | | | | |
. | | | | | | | _|_ 1 | | | | | |
. _|_| _|_| _|_| _|_| |_| _|_| _|_| _|_| _
. | | | | | | | | | | | | | | | |
. | | | | | | |_|_ _ _| | | | | | | |
. | | | | | | 2 |_ _|_ _| _| | | | | | |
. | | | | |_|_ 2 |_ _ _| 0 _ _| | | | | |
. | | | | 4 |_ 7 _| _ _|0 | | | |
. | | |_|_ _ 0 |_ _ _ _ | _| _ _ _| | | |
. | | 6 |_ |_ _ _ _|_ _ _ _| | 0 _| _ _ _|0 | |
. |_|_ _ _ 0 |_ 4 |_ _ _ _ _| _| _| | _ _ _| |
. 8 | |_ _ 0 | 15| _| _| | _ _ _|
. |_ _ | |_ _ _ _ _ _ | |_ _| 0 _| | 0
. 7 |_| |_ |_ _ _ _ _ _|_ _ _ _ _ _| | 5 _| _|
. 1 |_ _| 6 |_ _ _ _ _ _ _| _ _| _| 0
. 0 | 23| _ _| 0
. |_ _ _ _ _ _ _ _ | | 0
. |_ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _| |
. 8 |_ _ _ _ _ _ _ _ _|
. 31
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The diagram contains 30 subparts equaling A060831(16), the total number of partitions of all positive integers <= 16 into consecutive parts.
For the construction of the spiral see A239660.
Also consider the infinite double-staircases diagram defined in A335616 (see the theorem). For n = 15 the diagram with first 15 levels looks like this:
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Level "Double-staircases" diagram
. _
1 _|1|_
2 _|1 _ 1|_
3 _|1 |1| 1|_
4 _|1 _| |_ 1|_
5 _|1 |1 _ 1| 1|_
6 _|1 _| |1| |_ 1|_
7 _|1 |1 | | 1| 1|_
8 _|1 _| _| |_ |_ 1|_
9 _|1 |1 |1 _ 1| 1| 1|_
10 _|1 _| | |1| | |_ 1|_
11 _|1 |1 _| | | |_ 1| 1|_
12 _|1 _| |1 | | 1| |_ 1|_
13 _|1 |1 | _| |_ | 1| 1|_
14 _|1 _| _| |1 _ 1| |_ |_ 1|_
15 |1 |1 |1 | |1| | 1| 1| 1|
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Starting from A196020 and after the algorithm described n A280850 and the conjecture applied to the above diagram we have a new diagram as shown below:
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Level "Ziggurat" diagram
. _
6 |1|
7 _ | | _
8 _|1| _| |_ |1|_
9 _|1 | |1 1| | 1|_
10 _|1 | | | | 1|_
11 _|1 | _| |_ | 1|_
12 _|1 | |1 1| | 1|_
13 _|1 | | | | 1|_
14 _|1 | _| _ |_ | 1|_
15 |1 | |1 |1| 1| | 1|
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The 15th row
of A249351: [1,1,1,1,1,1,1,1,0,0,0,1,1,1,2,1,1,1,0,0,0,1,1,1,1,1,1,1,1]
The 15th row
The 15th row
of this seq: [ 8, 7, 1, 0, 8 ]
The 15th row
.
(End)
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CROSSREFS
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The number of nonzero terms in row n is A001227(n).
The triangle with n rows contain A060831(n) nonzero terms.
Cf. A024916, A196020, A235791, A236104, A237048, A237270, A237591, A237593, A238005, A239657, A239660, A239931-A239934, A240542, A244050, A245092, A250068, A250070, A261699, A262626, A279387, A279388, A279391, A280850.
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KEYWORD
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nonn,tabf
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AUTHOR
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STATUS
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approved
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