A336012 - cp's OEIS frontend

A336012 a(n) is the number of chains from {} to a top element in the poset of even sized subsets of {1,2,...,n} ordered by inclusion.

n	a(n)
0	1
1	1
2	1
3	3
4	7
5	35
6	121
7	847
8	3907
9	35163
10	202741
11	2230151
12	15430207
13	200592691
14	1619195761
15	24287936415
16	224061282907
17	3809041809419
18	39531606447181
19	751100522496439
20	8661323866026007
21	181887801186546147
22	2307185279184885001
23	53065261421252355023
24	734307168916191403507
25	18357679222904785087675

[1, 1, 1, 3, 7, 35, 121, 847, 3907, 35163, 202741, 2230151, 15430207, 200592691, 1619195761, 24287936415, 224061282907, 3809041809419, 39531606447181, 751100522496439, 8661323866026007, 181887801186546147, 2307185279184885001, 53065261421252355023, 734307168916191403507, 18357679222904785087675]

cp's OEIS Frontend

A336012 a(n) is the number of chains from {} to a top element in the poset of even sized subsets of {1,2,...,n} ordered by inclusion.

Table of values

List of values