Eric Angelini: > Let us start with 11; is 11 divisible by (1+1)=2? > No. We then add 2 to 11 => 13 > > Is 13 divisible by (1+3)=4? > No. We then add 4 to 13 => 17 Suppose we multiply our number by the sum of its digits to get the next number: http://chesswanks.com/blahg/odo/Blog/Entries/2010/9/29_Accumulating_factors.html