472393

This number is a prime.

Just showing those entries submitted by 'Hartley': (Click here to show all)

If a number can be written both as 2a² + 1 and as 3b³ + 1, it must be of the form 648k⁶ + 1. The smallest prime of this form is not only 472393, where k = 3, but curiously k = 4 and k = 5 also. [Hartley]