A140945 - cp's OEIS frontend

A140945 Triangle read by rows: counts series-parallel networks by the number of series connections.

n	a(n)
1	1
2	1
3	1
4	1
5	6
6	1
7	1
8	25
9	25
10	1
11	1
12	90
13	290
14	90
15	1
16	1
17	301
18	2450
19	2450
20	301
21	1
22	1
23	966
24	17451
25	41580
26	17451
27	966
28	1
29	1
30	3025
31	112035
32	544971
33	544971
34	112035
35	3025
36	1
37	1
38	9330
39	671980
40	6076350
41	12122502
42	6076350
43	671980
44	9330
45	1
46	1
47	28501
48	3846700
49	60738700
50	217523922
51	217523922
52	60738700
53	3846700
54	28501
55	1

[1, 1, 1, 1, 6, 1, 1, 25, 25, 1, 1, 90, 290, 90, 1, 1, 301, 2450, 2450, 301, 1, 1, 966, 17451, 41580, 17451, 966, 1, 1, 3025, 112035, 544971, 544971, 112035, 3025, 1, 1, 9330, 671980, 6076350, 12122502, 6076350, 671980, 9330, 1, 1, 28501, 3846700, 60738700, 217523922, 217523922, 60738700, 3846700, 28501, 1]

cp's OEIS Frontend

A140945 Triangle read by rows: counts series-parallel networks by the number of series connections.

Table of values

List of values