16
This number is a composite.
Just showing those entries submitted by 'Capelle': (Click here to show all)
16 is the smallest square which is difference of two prime squares. [Capelle]
The smallest square whose reverse is prime. [Capelle]
222 is the smallest number n such that 3 + n, (3*5) + n, (3*5*17) + n, (3*5*17*257) + n, (3*5*17*257*65537) + n are all primes. Note that 3, 5, 17, 257 and 65537 are the known Fermat primes, with the property (F0*F1*F2*...*Fn-1) + 2 = Fn [Capelle]
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