A204420 - cp's OEIS frontend

A204420 Triangle T(n,k) giving number of degree-2n permutations which decompose into exactly k cycles of even length, k=0..n.

n	a(n)
0	1
1	0
2	1
3	0
4	6
5	3
6	0
7	120
8	90
9	15
10	0
11	5040
12	4620
13	1260
14	105
15	0
16	362880
17	378000
18	132300
19	18900
20	945
21	0
22	39916800
23	45571680
24	18711000
25	3534300
26	311850
27	10395
28	0
29	6227020800
30	7628100480
31	3511347840
32	794593800
33	94594500
34	5675670
35	135135

[1, 0, 1, 0, 6, 3, 0, 120, 90, 15, 0, 5040, 4620, 1260, 105, 0, 362880, 378000, 132300, 18900, 945, 0, 39916800, 45571680, 18711000, 3534300, 311850, 10395, 0, 6227020800, 7628100480, 3511347840, 794593800, 94594500, 5675670, 135135]

cp's OEIS Frontend

A204420 Triangle T(n,k) giving number of degree-2n permutations which decompose into exactly k cycles of even length, k=0..n.

Table of values

List of values