px or =1, M=product of the lacking primes up to px or =1, then

abs(N+-M) is prime, if less than (px+1)².

Ex.: 2*5*11 +- 3*7 = 131,89, both prime because less than 13²=169.

Thus one can observe an embracing symmetry within small prime numbers.

Generalization: instead of primes choose powers of primes.

Werner