A334257 - cp's OEIS frontend

A334257 Triangle read by rows: T(n,k) is the number of ordered pairs of n-permutations with exactly k common double descents, n>=0, 0<=k<=max{0,n-2}.

n	a(n)
0	1
1	1
2	4
3	35
4	1
5	545
6	30
7	1
8	13250
9	1101
10	48
11	1
12	463899
13	51474
14	2956
15	70
16	1
17	22106253
18	3070434
19	217271
20	7545
21	96
22	1
23	1375915620
24	229528818
25	19372881
26	864632
27	20322
28	126
29	1
30	108386009099
31	21107789247
32	2070917370
33	113587335
34	3530099
35	61089
36	160
37	1

[1, 1, 4, 35, 1, 545, 30, 1, 13250, 1101, 48, 1, 463899, 51474, 2956, 70, 1, 22106253, 3070434, 217271, 7545, 96, 1, 1375915620, 229528818, 19372881, 864632, 20322, 126, 1, 108386009099, 21107789247, 2070917370, 113587335, 3530099, 61089, 160, 1]

cp's OEIS Frontend

A334257 Triangle read by rows: T(n,k) is the number of ordered pairs of n-permutations with exactly k common double descents, n>=0, 0<=k<=max{0,n-2}.

Table of values

List of values