A vertical channel 3D NAND array is configured for independent double gate operation, establishing two memory sites per frustum of a vertical channel column, and in addition, for multiple-bit-per-cell operation. The memory device can comprise even and odd stacks of conductive strips. Active pillars are arranged between corresponding even and odd stacks of conductive strips. A 3D array includes even memory cells accessible via the active pillars and conductive strips in the even stacks and odd memory cells accessible via the active pillars and conductive strips in the odd stacks of conductive strips. Control circuitry is configured to apply different bias voltages to the even and odd conductive strips, and execute a program operation by which more than one bit of data is stored in both the even memory cell and odd memory cell in a given frustum of a selected active strip.