9 -6 =3
15 -9 =6
22 -15 =7
51 -22 =29
99 -51 =48
So Ignoring the difference between the terms where one of the terms is 22 all other differences are multiple of 3
So 22 is the wrong term and the correct series would have been
9 -6 = 3 x 1
15 -9 = 3 x 2
27 -15 = 3 x 4
51 -27 = 3 x 8
99 -51 = 3 x 16
So 22 is the wrong term
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