Number of permutations of length n, in which all monotone subsequences of length 4 are descending or all such subsequences are ascending, containing the minimum number of such subsequences subject to that constraint.
A079105
Number of permutations of length n, in which all monotone subsequences of length 4 are descending or all such subsequences are ascending, containing the minimum number of such subsequences subject to that constraint.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =22a(5) =86a(6) =306a(7) =882a(8) =1764a(9) =1764a(10) =8738a(11) =6892a(12) =1682a(13) =4614a(14) =4182a(15) =1250a(16) =3750a(17) =3750a(18) =1250a(19) =3750a(20) =3750a(21) =1250a(22) =3750a(23) =3750a(24) =1250a(25) =3750a(26) =3750a(27) =1250a(28) =3750a(29) =3750
External references
- oeis: A079105