A024220 a(n) = [ (3rd elementary symmetric function of S(n))/(first elementary symmetric function of S(n)) ], where S(n) = {first n+2 positive integers congruent to 1 mod 3}.

2, 19, 71, 188, 410, 784, 1367, 2226, 3435, 5078, 7249, 10049, 13589, 17990, 23380, 29897, 37689, 46911, 57728, 70315, 84854, 101537, 120566, 142150, 166508, 193869, 224469, 258554, 296380, 338210, 384317, 434984, 490501, 551168, 617295, 689199