Gradient colors are often recommended by color specialists or designers based on the specific design context and the desired aesthetic. A recommended color number for a gradient typically refers to a specific shade or hue that complements the overall design theme. To suggest a color number, one would consider factors such as the color harmony, the intended mood of the design, and the medium in which the gradient will be applied (e.g., digital, print, etc.). For a specific recommendation, more details about the design requirements would be needed.