Number of ways of ordering integers 1 to n such that each number is either a factor of or larger than its predecessor.

A263987

Number of ways of ordering integers 1 to n such that each number is either a factor of or larger than its predecessor.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =14a(5) =28a(6) =164a(7) =328a(8) =2240a(9) =9970a(10) =63410a(11) =126820a(12) =1810514a(13) =3621028a(14) =31417838a(15) =294911038a(16) =3344414606a(17) =6688829212a(18) =121919523980a(19) =243839047960

External references