A162979 - cp's OEIS frontend

A162979 Triangle read by rows: T(n,k) is the number of alternating (i.e., down-up) permutations of {1,2,...,n} having k fixed points (n >= 0, 0 <= k <= ceiling(n/2)).

n	a(n)
0	1
1	0
2	1
3	1
4	0
5	1
6	1
7	0
8	2
9	2
10	1
11	6
12	6
13	3
14	1
15	24
16	24
17	11
18	2
19	102
20	102
21	51
22	15
23	2
24	528
25	528
26	252
27	68
28	9
29	2952
30	2952
31	1476
32	458
33	89
34	9
35	19008
36	19008
37	9240
38	2728
39	493
40	44
41	131112
42	131112
43	65556
44	20868
45	4479
46	621
47	44
48	1009728
49	1009728
50	495360
51	152448
52	31182
53	4054
54	265
55	8271792
56	8271792
57	4135896
58	1334928
59	300954
60	47670
61	4959
62	265

[1, 0, 1, 1, 0, 1, 1, 0, 2, 2, 1, 6, 6, 3, 1, 24, 24, 11, 2, 102, 102, 51, 15, 2, 528, 528, 252, 68, 9, 2952, 2952, 1476, 458, 89, 9, 19008, 19008, 9240, 2728, 493, 44, 131112, 131112, 65556, 20868, 4479, 621, 44, 1009728, 1009728, 495360, 152448, 31182, 4054, 265, 8271792, 8271792, 4135896, 1334928, 300954, 47670, 4959, 265]

cp's OEIS Frontend

A162979 Triangle read by rows: T(n,k) is the number of alternating (i.e., down-up) permutations of {1,2,...,n} having k fixed points (n >= 0, 0 <= k <= ceiling(n/2)).

Table of values

List of values