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A095288
Least middle side of 2^n primitive arithmetic triangles, i.e. primitive Heronian triangles whose sides are in arithmetic progression.
6916 is the first middle side belonging to 2^3=8 arithmetic triangles,viz,(3485,6916,10347),(3747,6916,10085),(4133,6916,9699),(4299,6916,9533),(4827,6916,9005),5045,6916,8787),(5333,6916,8499),(6267,6916,7565) of common differences 3431,3169,2783,2617,2089,1871,1583,649 respectively and integral areas.(Perimeter is obviously three times middle side and hence the same for all the triangles)