Triangle read by rows: T(n,k) is the number of permutations of [n] having k adjacent 4-cycles (0 <= k <= floor(n/4)), i.e., having k cycles of the form (i, i+1, i+2, i+3).
A177252
Triangle read by rows: T(n,k) is the number of permutations of [n] having k adjacent 4-cycles (0 <= k <= floor(n/4)), i.e., having k cycles of the form (i, i+1, i+2, i+3).
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =23a(5) =1a(6) =118a(7) =2a(8) =714a(9) =6a(10) =5016a(11) =24a(12) =40201a(13) =118a(14) =1a(15) =362163a(16) =714a(17) =3a(18) =3623772a(19) =5016a(20) =12a(21) =39876540a(22) =40200a(23) =60a(24) =478639079a(25) =362163a(26) =357a(27) =1a(28) =6223394516a(29) =3623772
External references
- oeis: A177252