A001894 - cp's OEIS frontend

A001894 Number of permutations of {1,...,n} having n-4 inversions (n>=4).

n	a(n)
4	1
5	4
6	14
7	49
8	174
9	628
10	2298
11	8504
12	31758
13	119483
14	452284
15	1720774
16	6574987
17	25214332
18	96997223
19	374153699
20	1446677555
21	5605337934
22	21758936146
23	84604366100
24	329453055975
25	1284626463105
26	5015200610785
27	19601107218591
28	76685359017750
29	300294650988857
30	1176939165980809

[1, 4, 14, 49, 174, 628, 2298, 8504, 31758, 119483, 452284, 1720774, 6574987, 25214332, 96997223, 374153699, 1446677555, 5605337934, 21758936146, 84604366100, 329453055975, 1284626463105, 5015200610785, 19601107218591, 76685359017750, 300294650988857, 1176939165980809]

cp's OEIS Frontend

A001894 Number of permutations of {1,...,n} having n-4 inversions (n>=4).

Table of values

List of values