[math-fun] A016142

This (also) appears to be 3^(n-1) * (3^n - 1)/2. VERY WILD surmise: It's the number of integer-sided Heron triangles whose circumdiameter is the product of n distinct primes of shape 4k + 1. (3^n - 1)/2 of these are (believed to be) right triangles, so that the number of non-right ones is (3^(n-1) - 1) * (3^n - 1)/2 A003462 and a new(?) sequence 0, 8, 104, 1040, 9680, ... R.