B11

B1D♯3F♯5A♭7C♯9E11

Six notes in theory; in practice the third is usually dropped, because the eleventh sits a half step above it.

What is true of it

B11 is B, D♯, F♯, A, C♯ and E — 1, 3, 5, b7, 9 and 11 counted from B.

On an instrument that cannot reach all 6, the 3, 5 and 1 go first, in that order.