A298122 - cp's OEIS frontend

A298122 a(n) is the number of n nonintersecting arches above the x-axis that start and/or end with an arch length equal to one and have floor((n+2)/2) arches starting in odd numbered positions.

n	a(n)
1	1
2	1
3	2
4	5
5	11
6	34
7	90
8	300
9	875
10	3038
11	9408
12	33516
13	108108
14	392040
15	1302444
16	4785066
17	16256955
18	60324550
19	208579800
20	780088452
21	2735682092
22	10296854984
23	36532677272
24	138231751840
25	495241833996
26	1882201158264
27	6799413051200
28	25939319270000
29	94374970110000

[1, 1, 2, 5, 11, 34, 90, 300, 875, 3038, 9408, 33516, 108108, 392040, 1302444, 4785066, 16256955, 60324550, 208579800, 780088452, 2735682092, 10296854984, 36532677272, 138231751840, 495241833996, 1882201158264, 6799413051200, 25939319270000, 94374970110000]

cp's OEIS Frontend

A298122 a(n) is the number of n nonintersecting arches above the x-axis that start and/or end with an arch length equal to one and have floor((n+2)/2) arches starting in odd numbered positions.

Table of values

List of values