A221881 - cp's OEIS frontend

A221881 Number of order-preserving or order-reversing full contraction mappings (of an n-chain) with (right) waist exactly k.

n	a(n)
1	1
2	1
3	3
4	1
5	5
6	7
7	1
8	7
9	13
10	15
11	1
12	9
13	21
14	29
15	31
16	1
17	11
18	31
19	51
20	61
21	63
22	1
23	13
24	43
25	83
26	113
27	125
28	127
29	1
30	15
31	57
32	127
33	197
34	239
35	253
36	255
37	1
38	17
39	73
40	185
41	325
42	437
43	493
44	509
45	511
46	1
47	19
48	91
49	259
50	511
51	763
52	931
53	1003
54	1021
55	1023

[1, 1, 3, 1, 5, 7, 1, 7, 13, 15, 1, 9, 21, 29, 31, 1, 11, 31, 51, 61, 63, 1, 13, 43, 83, 113, 125, 127, 1, 15, 57, 127, 197, 239, 253, 255, 1, 17, 73, 185, 325, 437, 493, 509, 511, 1, 19, 91, 259, 511, 763, 931, 1003, 1021, 1023]

cp's OEIS Frontend

A221881 Number of order-preserving or order-reversing full contraction mappings (of an n-chain) with (right) waist exactly k.

Table of values

List of values