Irregular triangle read by rows: T(n,k) = number of size k subsets of S_n that remain unchanged by reverse.
A277080
Irregular triangle read by rows: T(n,k) = number of size k subsets of S_n that remain unchanged by reverse.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =0a(6) =1a(7) =1a(8) =0a(9) =3a(10) =0a(11) =3a(12) =0a(13) =1a(14) =1a(15) =0a(16) =12a(17) =0a(18) =66a(19) =0a(20) =220a(21) =0a(22) =495a(23) =0a(24) =792a(25) =0a(26) =924a(27) =0a(28) =792a(29) =0
External references
- oeis: A277080