Given the sequence 201, 212, 223, 234
The sequence has been represented by the general formula
A(n) = 201 + (n - 1)11
where n is the number of terms
Hence where n = 12,
A (12) = 201 + (12 - 1)11
= 201 + 11*11
= 201 + 121
= 322
The expression using the nth variable is A(n) = 201 + (n - 1)11
A(12) = 322