7, 8, 18, 57, 228, 1165, 6996?

Let the given number be A, B, C, D, E, F, G. Then A x 1 + 1, B x 2 + 2, C x 3 + 3, D x 4 + 4, E x 5 + 5, F x 6 + 6 are the required number . Clearly, 228 is wrong.