Try this trick with KORG Monologue sequencer and NTS-1 arpeggiator - @brianleahyart 

Sweet! Agreed, it's a nice way to mix things up with the sequencer

So you'll need a 3.5mm TRS-to-MIDI cable adapter, as well as a standard 5-pin MIDI cable. Note that there are 2 types of 3.5mm TRS-to-MIDI cables: type A and type B. Type B will not work with the NTS-1. I use this Type A one: www.sweetwater.com/store/detail/0-COASTMidi--make-noise-0-coast-midi-cable-1-8-inch-trs-to-5-pin-midi You plug this adapter into the NTS-1's MIDI In jack, and then attach the standard 5-pin MIDI cable to it - this is what you plug into the Monologue's MIDI Out. The result is the Monologue's sequencer sending MIDI notes to the NTS-1, which the NTS-1 is then applying to its arp. Fun to note - you are only hearing the output from the NTS-1 here. Technically you could also record the Monologue's output as well at the same time, for 2 different layers of sound!