Here's a pattern...
[11*26 + 1 ] / 7 = 41
[25*26 + 1] / 7 = 93
[39*26 + 1 ] / 7 = 145
[53*26 + 1 ] = 197
So....it appears that the pattern [(-3 ± 14n) *26 + 1 ] / 7 will produce an integer ....for n= 0, 1, 2, 3......
So "X" must be, in general, [41 ± 52k] for k = 0, 1, 2, 3........
