Triangle T(n,k) read by rows: T(n,k) = number of ways of seating n people around a table for the second time so that k pairs are maintained. Reflected sequences are counted as one.
A326397
Triangle T(n,k) read by rows: T(n,k) = number of ways of seating n people around a table for the second time so that k pairs are maintained. Reflected sequences are counted as one.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =0a(4) =0a(5) =1a(6) =0a(7) =0a(8) =0a(9) =3a(10) =0a(11) =0a(12) =8a(13) =0a(14) =4a(15) =5a(16) =0a(17) =25a(18) =25a(19) =0a(20) =5a(21) =18a(22) =72a(23) =90a(24) =120a(25) =54a(26) =0a(27) =6a(28) =161a(29) =490
External references
- oeis: A326397