Verse / prechorus / bridge:
A5 Bb5 G5 A5
Chorus:
A5 A5 A5 A5 A5 Bb5 A5
Synthesizer
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2-2-2-2-2-3-2------------|
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You can even go an octave higher on the little chorus lick.
Source: https://tabs.ultimate-guitar.com/tab/justin_timberlake/sexyback_chords_972508
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