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

A180386

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

Terms

    a(0) =4a(1) =12a(2) =69a(3) =143a(4) =1051a(5) =1041a(6) =6722a(7) =8485a(8) =15907a(9) =8500a(10) =71585a(11) =72304a(12) =374159a(13) =192093a(14) =132237a(15) =83720a(16) =495591a(17) =405716a(18) =2262354a(19) =2347020a(20) =1676501a(21) =478044a(22) =3315250a(23) =5160917a(24) =5831333a(25) =1762619a(26) =2192192a(27) =1666381a(28) =8506917a(29) =12211917

External references