A177482 - cp's OEIS frontend

A177482 Suppose e and g To avoid fegh means not to have four consecutive letters such that the second and the third letters are less than the first and the fourth letters.

n	a(n)
0	1
1	1
2	2
3	6
4	20
5	80
6	360
7	1888
8	11168
9	75168
10	560960
11	4632320
12	41627520
13	405993472
14	4256566784
15	47855992320
16	573443425280
17	7304885964800
18	98493107742720
19	1402190308089856
20	21008850635694080
21	330557870033510400
22	5448181151148032000
23	93883859983130624000

[1, 1, 2, 6, 20, 80, 360, 1888, 11168, 75168, 560960, 4632320, 41627520, 405993472, 4256566784, 47855992320, 573443425280, 7304885964800, 98493107742720, 1402190308089856, 21008850635694080, 330557870033510400, 5448181151148032000, 93883859983130624000]

cp's OEIS Frontend

A177482 Suppose e and g To avoid fegh means not to have four consecutive letters such that the second and the third letters are less than the first and the fourth letters.

Table of values

List of values