A045992 - cp's OEIS frontend

A045992 a(n) = binomial(2n,n) - n; number of (weakly) increasing or decreasing maps from 1,...,n to 1,...,n.

n	a(n)
0	1
1	1
2	4
3	17
4	66
5	247
6	918
7	3425
8	12862
9	48611
10	184746
11	705421
12	2704144
13	10400587
14	40116586
15	155117505
16	601080374
17	2333606203
18	9075135282
19	35345263781
20	137846528800
21	538257874419
22	2104098963698
23	8233430727577
24	32247603683076

[1, 1, 4, 17, 66, 247, 918, 3425, 12862, 48611, 184746, 705421, 2704144, 10400587, 40116586, 155117505, 601080374, 2333606203, 9075135282, 35345263781, 137846528800, 538257874419, 2104098963698, 8233430727577, 32247603683076]

cp's OEIS Frontend

A045992 a(n) = binomial(2n,n) - n; number of (weakly) increasing or decreasing maps from 1,...,n to 1,...,n.

Table of values

List of values