Question 1126398
{{{system(even_integers,n-2,n,n+2)}}}


{{{n(n+2)=-6+21(n-2)}}}

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{{{n^2+2n=21n-42-6}}}

{{{n^2-19n+48=0}}}


{{{(n-16)(n-3)=0}}}


The MIDDLE integer is  16.



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You don't want 3, because 3 is not an "even" integer.  But 16 is even.
Numbers:  14, 16, 18