4x 1 9x 16 July 8, 2019 16 32 64 128 1 4x 9x 2 16x 3 upto infinity 1 4x 9x 2 16x 3 1 4x 9x 2 16x 3 formula 6x 1 2 4x 1 9x 2 16 4x4 = 16