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).
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).
Terms
- a(0) =1a(1) =2a(2) =7a(3) =28a(4) =116a(5) =490a(6) =2094a(7) =9014a(8) =38988a(9) =169184a(10) =735846a(11) =3205830a(12) =13984076a(13) =61057108a(14) =266780436a(15) =1166320956a(16) =5101254296a(17) =22319861332a(18) =97685806958a(19) =427635145446
External references
- oeis: A061539