a(n) = smallest k such that tau(k)= n*tau(k-1) where tau(k) = number of divisors of k, or 0 if no such number exists.

A086551

a(n) = smallest k such that tau(k)= n*tau(k-1) where tau(k) = number of divisors of k, or 0 if no such number exists.

Terms

    a(0) =3a(1) =2a(2) =12a(3) =24a(4) =48a(5) =60a(6) =192a(7) =168a(8) =180a(9) =240a(10) =5120a(11) =360a(12) =20480a(13) =2112a(14) =720a(15) =840a(16) =983040a(17) =1260a(18) =786432a(19) =3024a(20) =2880a(21) =15360a(22) =62914560a(23) =3360a(24) =22032a(25) =266240a(26) =6300a(27) =6720a(28) =13690208256a(29) =5040

External references