C 13#11, 5th inversion (F# in the bass)
Also written as C13#11/F#.
Notes, from the bass up
F# (bass)ACEGBbD
The same notes as C 13#11 (F#, A, C, E, G, Bb and D), rearranged so F# is the lowest note. Use it to move between chords with smaller jumps across the keyboard.