|
|
A279029
|
|
Numbers k with the property that the smallest and the largest Dyck path of the symmetric representation of sigma(k) do not share line segments.
|
|
5
|
|
|
1, 2, 3, 4, 6, 8, 10, 12, 16, 18, 20, 24, 28, 30, 32, 36, 40, 42, 48, 54, 56, 60, 64, 66, 72, 78, 80, 84, 88, 90, 96, 100, 104, 108, 112, 120, 126, 128, 132, 136, 140, 144, 150, 156, 160, 162, 168, 176, 180, 192, 196, 198, 200, 204, 208, 210, 216, 220, 224, 228, 234, 240, 252, 256
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
Numbers k such that the symmetric representation of sigma(k) is formed by only one part, or that it's formed by only two parts and they meet at the center.
Numbers k whose total length of all line segments of the symmetric representation of sigma(k) is equal to 4*k (cf. A348705). For the positive integers k that are not in this sequence the mentioned total length is < 4*k. - Omar E. Pol, Nov 02 2021
|
|
LINKS
|
|
|
EXAMPLE
|
1, 2, 3, 4, 6, 8, 10, 12 and 16 are in the sequence because the smallest and the largest Dyck path of their symmetric representation of sigma do not share line segments, as shown below.
llustration of initial terms:
n
. _ _ _ _ _ _ _ _ _
1 |_| | | | | | | | | | | | | |
2 |_ _|_| | | | | | | | | | | |
3 |_ _| _|_| | | | | | | | | |
4 |_ _ _| _|_| | | | | | | |
_ _ _| _| _ _|_| | | | | |
6 |_ _ _ _| _| | _ _|_| | | |
_ _ _ _| |_ _|_| _ _| | |
8 |_ _ _ _ _| _| | _ _ _| |
_ _ _ _ _| | _| | _ _ _|
10 |_ _ _ _ _ _| _ _| _| |
_ _ _ _ _ _| | _| _|
12 |_ _ _ _ _ _ _| _ _| _|
| _ _|
| |
_ _ _ _ _ _ _ _| |
16 |_ _ _ _ _ _ _ _ _|
...
|
|
CROSSREFS
|
Indices of nonzero terms in A279228.
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|