253679

This number is a prime.

+ The smallest first member of a Twin primes pair (a,b) such that (a+b) +/- 1 is a second Twin primes pair (c,d) such that (c+d) +/- 1 is a third Twin primes pair (e,f) such that (e+f) +/- 1 is a fourth Twin primes pair (g,h). [De Geest]

(There is one curio for this number that has not yet been approved by an editor.)

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