A129535 - cp's OEIS frontend

A129535 Number of permutations of 1,...,n with at least one pair of adjacent consecutive entries (i.e., of the form k(k+1) or (k+1)k), n >= 2.

n	a(n)
2	2
3	6
4	22
5	106
6	630
7	4394
8	35078
9	315258
10	3149494
11	34620010
12	415222566
13	5395737242
14	75516784982
15	1132471183626
16	18115911832390
17	307919970965434
18	5541804787940598
19	105282261866132138
20	2105441434230129254
21	44210612765653749210
22	972564180363044943766

[2, 6, 22, 106, 630, 4394, 35078, 315258, 3149494, 34620010, 415222566, 5395737242, 75516784982, 1132471183626, 18115911832390, 307919970965434, 5541804787940598, 105282261866132138, 2105441434230129254, 44210612765653749210, 972564180363044943766]

cp's OEIS Frontend

A129535 Number of permutations of 1,...,n with at least one pair of adjacent consecutive entries (i.e., of the form k(k+1) or (k+1)k), n >= 2.

Table of values

List of values