Where t(n) is the n-th 10-step Fibonacci number as defined by: a(0...8)=0,, a(9)=1 and a(n)=a(n-1)+a(n-2)+...+a(n-10) t(689900) = 2225786121...5661540351 Verified Fermat and Lucas PRP by pfgw.
To be completed...