A061539 - cp's OEIS frontend

A061539 Number of signed permutations in B_n which correspond to smooth Schubert varieties. These permutations avoid the following patterns: (-2 -1) (1 2 -3) (1 -2 -3) (-1 2 -3) (2 -1 -3) (-2 1 -3) (3 -2 1) (2 -4 3 1) (-2 -4 3 1) (3412) (3 4 -1 2) (-3 4 1 2) (4 1 3 -2) (4 -1 3 -2) (4 2 3 1) (4 2 3 -1) (-4 2 3 1).

n	a(n)
0	1
1	2
2	7
3	28
4	116
5	490
6	2094
7	9014
8	38988
9	169184
10	735846
11	3205830
12	13984076
13	61057108
14	266780436
15	1166320956
16	5101254296
17	22319861332
18	97685806958
19	427635145446
20	1872400460940
21	8199602319764
22	35912342632908
23	157304824211156
24	689096352589448
25	3018916616772272

[1, 2, 7, 28, 116, 490, 2094, 9014, 38988, 169184, 735846, 3205830, 13984076, 61057108, 266780436, 1166320956, 5101254296, 22319861332, 97685806958, 427635145446, 1872400460940, 8199602319764, 35912342632908, 157304824211156, 689096352589448, 3018916616772272]

cp's OEIS Frontend

Table of values

List of values