A188498 - cp's OEIS frontend

A188498 Number of permutations p on the set [n] with the properties that abs(p(i)-i) <= 3 for all i, p(1) <= 2, and p(j) >= 2 for j=3,4.

n	a(n)
0	0
1	1
2	2
3	3
4	8
5	30
6	102
7	308
8	905
9	2744
10	8473
11	26112
12	79924
13	244204
14	747160
15	2288521
16	7009458
17	21461803
18	65704200
19	201162258
20	615922714
21	1885853660
22	5774072225
23	17678809840
24	54128358209
25	165728860112
26	507424764216
27	1553620027784
28	4756831354752

[0, 1, 2, 3, 8, 30, 102, 308, 905, 2744, 8473, 26112, 79924, 244204, 747160, 2288521, 7009458, 21461803, 65704200, 201162258, 615922714, 1885853660, 5774072225, 17678809840, 54128358209, 165728860112, 507424764216, 1553620027784, 4756831354752]

cp's OEIS Frontend

A188498 Number of permutations p on the set [n] with the properties that abs(p(i)-i) <= 3 for all i, p(1) <= 2, and p(j) >= 2 for j=3,4.

Table of values

List of values