Let operator D(n) be the number formed by concatenation of the products of the decimal digits of n by their respective multiplicities. This sequence records the smallest number requiring n iterations of D to reach a stationary number; see Comment and Example.

A378022

Let operator D(n) be the number formed by concatenation of the products of the decimal digits of n by their respective multiplicities. This sequence records the smallest number requiring n iterations of D to reach a stationary number; see Comment and Example.

Terms

    a(0) =1a(1) =11a(2) =112a(3) =166a(4) =688a(5) =4468a(6) =22468a(7) =112468a(8) =124699a(9) =1678999a(10) =111367788889

External references