A370485 - cp's OEIS frontend

A370485 Number of permutations of [n] with the property that no subsequence k(k+1)(k+2) or (k+2)(k+1)k occurs but k(k+1) or (k+1)k occurs.

n	a(n)
0	0
1	0
2	2
3	4
4	16
5	78
6	480
7	3436
8	28050
9	256868
10	2607584
11	29061022
12	352747696
13	4632195548
14	65432845858
15	989341728564
16	15942876295728
17	272777484786062
18	4938657746907200
19	94332342088674252
20	1895781452461383986
21	39987981759263286340
22	883322358371147863168

[0, 0, 2, 4, 16, 78, 480, 3436, 28050, 256868, 2607584, 29061022, 352747696, 4632195548, 65432845858, 989341728564, 15942876295728, 272777484786062, 4938657746907200, 94332342088674252, 1895781452461383986, 39987981759263286340, 883322358371147863168]

cp's OEIS Frontend

A370485 Number of permutations of [n] with the property that no subsequence k(k+1)(k+2) or (k+2)(k+1)k occurs but k(k+1) or (k+1)k occurs.

Table of values

List of values