dsolve(ODE, y(x), 'series')
dsolve(ODE, y(x), 'series', x=pt)
dsolve({ODE, ICs}, y(x), 'series')
dsolve({sysODE, ICs}, {funcs}, 'series')
dsolve(ODE, y(x), 'type=series')
dsolve(ODE, y(x), 'type=series', x=pt)
dsolve({ODE, ICs}, y(x), 'type=series')
dsolve({sysODE, ICs}, {funcs}, 'type=series')