Number of permutations of [n] containing exactly 2 increasing subsequences of length 3.

A001089

Number of permutations of [n] containing exactly 2 increasing subsequences of length 3.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =3a(5) =24a(6) =133a(7) =635a(8) =2807a(9) =11864a(10) =48756a(11) =196707a(12) =783750a(13) =3095708a(14) =12152855a(15) =47500635a(16) =185082495a(17) =719559600a(18) =2793121080a(19) =10830450780a(20) =41965864794a(21) =162539516448a(22) =629399492330

External references