A367495 - cp's OEIS frontend

A367495 Number of up-down permutations p of [n] such that for all i the number of elements p(j) between p(i) and p(i+1) for j>i+1 differs from the number of elements p(k) between p(i+1) and p(i+2) for k>i+2.

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	4
6	11
7	37
8	147
9	684
10	3611
11	21345
12	139794
13	1004293
14	7853728
15	66413562
16	603851552
17	5874507617
18	60886603188
19	669797203196
20	7794401498440
21	95662364870740
22	1234953443995817
23	16728449735374081
24	237245379727483160
25	3515622139828164851

[1, 1, 1, 1, 2, 4, 11, 37, 147, 684, 3611, 21345, 139794, 1004293, 7853728, 66413562, 603851552, 5874507617, 60886603188, 669797203196, 7794401498440, 95662364870740, 1234953443995817, 16728449735374081, 237245379727483160, 3515622139828164851]

cp's OEIS Frontend

A367495 Number of up-down permutations p of [n] such that for all i the number of elements p(j) between p(i) and p(i+1) for j>i+1 differs from the number of elements p(k) between p(i+1) and p(i+2) for k>i+2.

Table of values

List of values