Number of increasing sequences of n integers x(1),...,x(n) with values in 1..4*n such that x(j) divides x(k) iff j divides k.

A180381

Number of increasing sequences of n integers x(1),...,x(n) with values in 1..4*n such that x(j) divides x(k) iff j divides k.

Terms

    a(0) =4a(1) =12a(2) =53a(3) =101a(4) =471a(5) =214a(6) =803a(7) =1037a(8) =1086a(9) =369a(10) =2002a(11) =618a(12) =3093a(13) =817a(14) =277a(15) =405a(16) =1974a(17) =967a(18) =5929a(19) =3567a(20) =2876a(21) =580a(22) =5174a(23) =3300a(24) =2903a(25) =598a(26) =563a(27) =562a(28) =5866a(29) =3324

External references