A061766 a(1) = 4; a(n) = smallest composite number of the form k*a(n-1) + 1.

4, 9, 10, 21, 22, 45, 46, 93, 94, 95, 96, 289, 290, 291, 292, 585, 586, 1173, 1174, 1175, 1176, 1177, 1178, 1179, 1180, 2361, 2362, 2363, 2364, 2365, 2366, 2367, 2368, 2369, 2370, 4741, 4742, 4743, 4744, 4745, 4746, 4747, 4748, 4749, 4750, 9501, 9502, 9503