Question

is 205 a term in sequences of 1,5,9,13

Answer 1

This is an arithmetic sequence, with common difference of 4, a = 1.

$a_{n}$ = a₁ + (n - 1)d
205 = 1 + (n - 1)4
204 = 4n - 4
208 = 4n
n = 52

So, yes. It is the 52nd term in the sequence.