This is LaTeX code:

[latex]
 
M(3^{2113}(3^{1989}-1), 3^{2113}(3^{1992}-1))= 
3^{2113}M(3^{1989}-1, 3^{1992}-1)= 
\
3^{2113}M(3^{1989}-1, 3^{1992}-1-3^{1989}+1)= 
\
3^{2113}M(3^{1989}-1, 3^{1989}(3^3-1))= 
\
3^{2113}M(3^{1989}-1, 26\cdot 3^{1989})

[/latex]