A226436 - cp's OEIS frontend

A226436 Number of permutations of {1..n} with fewer than 3 interior elements having values lying between the values of their neighbors.

n	a(n)
0	1
1	1
2	2
3	6
4	24
5	118
6	658
7	4078
8	27724
9	205134
10	1641534
11	14132390
12	130299584
13	1281352790
14	13391026730
15	148237230942
16	1733059331604
17	21341010960286
18	276120222880246
19	3745333514843734
20	53149568086851784
21	787599172764342822
22	12166057777073762082

[1, 1, 2, 6, 24, 118, 658, 4078, 27724, 205134, 1641534, 14132390, 130299584, 1281352790, 13391026730, 148237230942, 1733059331604, 21341010960286, 276120222880246, 3745333514843734, 53149568086851784, 787599172764342822, 12166057777073762082]

cp's OEIS Frontend

A226436 Number of permutations of {1..n} with fewer than 3 interior elements having values lying between the values of their neighbors.

Table of values

List of values