The borel(expr, a(n)) command computes the Borel transform of a generating function.

If  is the sequence of numbers defined by the recurrence expr, the borel function computes the recurrence for the numbers .

If  is the sequence of numbers defined by the recurrence expr, the procedure computes the recurrence for the numbers .

If t is specified as 'diffeq', expr is considered as a linear differential equation with polynomial coefficients for the function . In this case, the function returns a linear differential equation satisfied by the Borel transform of .