Number T(n,k) of permutations of [n] with exactly k (possibly overlapping) occurrences of the consecutive step pattern up, down, down, up; triangle T(n,k), n>=0, 0<=k<=max(0,floor((n-2)/3)), read by rows.
A230695
Number T(n,k) of permutations of [n] with exactly k (possibly overlapping) occurrences of the consecutive step pattern up, down, down, up; triangle T(n,k), n>=0, 0<=k<=max(0,floor((n-2)/3)), read by rows.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =24a(5) =109a(6) =11a(7) =588a(8) =132a(9) =3654a(10) =1386a(11) =26125a(12) =13606a(13) =589a(14) =209863a(15) =139714a(16) =13303a(17) =1876502a(18) =1508756a(19) =243542a(20) =18441367a(21) =17429745a(22) =3953529a(23) =92159a(24) =197776850a(25) =214536114a(26) =63334182a(27) =3354454a(28) =2297242583a(29) =2815529811
External references
- oeis: A230695