Number of increasing sequences of n integers x(1),...,x(n) with values in 1..3*n such that x(j) divides x(k) iff j divides k.

A180380

Number of increasing sequences of n integers x(1),...,x(n) with values in 1..3*n such that x(j) divides x(k) iff j divides k.

Terms

    a(0) =3a(1) =8a(2) =25a(3) =45a(4) =136a(5) =57a(6) =190a(7) =260a(8) =233a(9) =70a(10) =222a(11) =130a(12) =366a(13) =116a(14) =145a(15) =108a(16) =354a(17) =226a(18) =842a(19) =808a(20) =763a(21) =182a(22) =876a(23) =817a(24) =790a(25) =191a(26) =192a(27) =191a(28) =1025a(29) =817

External references