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