FUNCTION : _etanm - symbolic form eta[n,m](tau)
CALLING SEQUENCE : _etanm(n,m)
PARAMETERS : n,m - positive integers
SYNOPSIS : _etanm(n,m) returns eta[n,m](tau)
EXAMPLES :
> with(thetaids):
> _etanm(5,1);
eta[5, 1](tau)
SEE ALSO :
_ETAnm, _ETAn, _etan