# 1021

This number is a prime.

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

Note that in the matrix product:

[ 1 0 ] [ 2 3 ] [ 2 3 ] = [ 2 1 ] [ 1 1 ] [ 5 7 ]1021 is prime, 2311 is prime, 2, 3, 5 and 7 are the first four primes (and incidentally, 2357 is prime). This is the only pair of 2-by-2 matrices with this property. [Hartley]

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