Hi,

this did not wotk because the second formula is than the first and the multicolumn
OTR tries to put half or less of the text into the second column, you can now force
a second column with the \column command after the first line or you switch both
formulas and the OTR can make two columns.

\starttext

\startitemize[columns,a]
\item $a_n=\frac{(-1)^n}{\sqrt{n}}-3$
\item $a_n=2+\frac{1}{n+1}$
\stopitemize

\startitemize[columns,a]
\item $a_n=2+\frac{1}{n+1}$ \column
\item $a_n=\frac{(-1)^n}{\sqrt{n}}-3$
\stopitemize

\stoptext

Wolfgang