The notes are D#4 D#5 C#4 D#4. Of course you may encounter other octavenumbers depending on the pitch settings on your synths. (I bet some people will now rip their hair off due to my amateurish note description )
I'm not yet sure what oscillators are involved or if there's any modulation going on, but the sound goes through a lowpassfilter where a lot is cut off, and it also has a very gentle LP envelope with medium decaytime and a high sustain.
Then it has a volume envelope with a little longer decay and maybe 75 % sustain, and then just a hint of releasetime.
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