A087967 GCD[ -1+2^n, n^2] is not a square number.

18, 36, 72, 90, 100, 126, 144, 147, 162, 180, 198, 200, 234, 252, 288, 294, 300, 306, 324, 342, 360, 396, 400, 414, 441, 450, 468, 504, 522, 558, 576, 588, 600, 612, 630, 648, 666, 684, 700, 720, 735, 738, 774, 792, 800, 810, 828, 846, 882, 900, 936, 954