A155517 - cp's OEIS frontend

A155517 Triangle read by rows: T(n,k) is the number of permutations p of {1,2,...,n} for which the number of j < ceiling(n/2) such that p(j) + p(n+1-j) = n+1 is equal to k (n>=1; 0<=k <=ceiling(n/2)).

n	a(n)
1	0
2	1
3	0
4	2
5	4
6	0
7	2
8	16
9	0
10	8
11	64
12	48
13	0
14	8
15	384
16	288
17	0
18	48
19	2880
20	1536
21	576
22	0
23	48
24	23040
25	12288
26	4608
27	0
28	384
29	208896
30	115200
31	30720
32	7680
33	0
34	384
35	2088960
36	1152000
37	307200
38	76800
39	0
40	3840
41	23193600
42	12533760
43	3456000
44	614400
45	115200
46	0
47	3840
48	278323200

[0, 1, 0, 2, 4, 0, 2, 16, 0, 8, 64, 48, 0, 8, 384, 288, 0, 48, 2880, 1536, 576, 0, 48, 23040, 12288, 4608, 0, 384, 208896, 115200, 30720, 7680, 0, 384, 2088960, 1152000, 307200, 76800, 0, 3840, 23193600, 12533760, 3456000, 614400, 115200, 0, 3840, 278323200]

cp's OEIS Frontend

A155517 Triangle read by rows: T(n,k) is the number of permutations p of {1,2,...,n} for which the number of j < ceiling(n/2) such that p(j) + p(n+1-j) = n+1 is equal to k (n>=1; 0<=k <=ceiling(n/2)).

Table of values

List of values