A sequence is anything done on a sequencer...

What gets confusing is whether or not your arranger CALLS it a 'sequencer'. Usually, a 'recorder' is something that records in audio, like the MP3 recorders on S900, and optionally on Korg's, etc., but Roland, just to screw with you, have a feature they call the 'Recorder', which is NOT audio. It is simply a special kind of sequencer that captures (as MIDI) the total output of your arranger, as you play it, then you store that as an SMF, and can then work on it, one track at a time, in the '16 Track Sequencer' for fine tuning and overdubbing, etc..

Are you confused, yet..? Mission accomplished! :
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An arranger is just a tool. What matters is what you build with it..!