# 341

This number is a composite.

Chinese mathematicians (circa 500 B.C.) erroneously believed that 2(2^(*n*-1)-1) is not divisible by *n* if *n* is not prime. This was disproved by Sarrus in 1819 with *n* = 341, i.e., the smallest pseudoprime to base two.

The smallest member of the series *n*(*n* + 1 ) - 1 which, if composite, is not the product of two smaller primes in the series of the form 10*k* - 1 or 10*k* + 1. [McNamara]

(There are 3 curios for this number that have not yet been approved by an editor.)

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