A321280 - cp's OEIS frontend

A321280 Number T(n,k) of permutations p of [n] with exactly k descents such that the up-down signature of p has nonnegative partial sums; triangle T(n,k), n>=0, 0<=k<=max(0,floor((n-1)/2)), read by rows.

n	a(n)
0	1
1	1
2	1
3	1
4	2
5	1
6	8
7	1
8	22
9	22
10	1
11	52
12	172
13	1
14	114
15	856
16	604
17	1
18	240
19	3488
20	7296
21	1
22	494
23	12746
24	54746
25	31238
26	1
27	1004
28	43628
29	330068
30	518324
31	1
32	2026
33	143244
34	1756878
35	5300418
36	2620708
37	1
38	4072
39	457536
40	8641800
41	43235304
42	55717312
43	1
44	8166
45	1434318
46	40298572
47	309074508
48	728888188
49	325024572

[1, 1, 1, 1, 2, 1, 8, 1, 22, 22, 1, 52, 172, 1, 114, 856, 604, 1, 240, 3488, 7296, 1, 494, 12746, 54746, 31238, 1, 1004, 43628, 330068, 518324, 1, 2026, 143244, 1756878, 5300418, 2620708, 1, 4072, 457536, 8641800, 43235304, 55717312, 1, 8166, 1434318, 40298572, 309074508, 728888188, 325024572]

cp's OEIS Frontend

A321280 Number T(n,k) of permutations p of [n] with exactly k descents such that the up-down signature of p has nonnegative partial sums; triangle T(n,k), n>=0, 0<=k<=max(0,floor((n-1)/2)), read by rows.

Table of values

List of values