A257198 - cp's OEIS frontend

A257198 Number of permutations of length n having exactly one descent such that the first element of the permutation is an odd number.

n	a(n)
1	0
2	0
3	2
4	6
5	16
6	36
7	78
8	162
9	332
10	672
11	1354
12	2718
13	5448
14	10908
15	21830
16	43674
17	87364
18	174744
19	349506
20	699030
21	1398080
22	2796180
23	5592382
24	11184786
25	22369596
26	44739216
27	89478458
28	178956942
29	357913912
30	715827852
31	1431655734
32	2863311498
33	5726623028

[0, 0, 2, 6, 16, 36, 78, 162, 332, 672, 1354, 2718, 5448, 10908, 21830, 43674, 87364, 174744, 349506, 699030, 1398080, 2796180, 5592382, 11184786, 22369596, 44739216, 89478458, 178956942, 357913912, 715827852, 1431655734, 2863311498, 5726623028]

cp's OEIS Frontend

A257198 Number of permutations of length n having exactly one descent such that the first element of the permutation is an odd number.

Table of values

List of values