What is the recursive formula for 3,7,11,15, ...

Arithmetic sequence: a_n=a_1 + (n-1) d where: d = common difference between terms; n = term; a_1 = first term of sequence a_n = 3 + (n-1) 4 = 3 + (4n-4) = 4n-1 Therefore, a_50 = 4 (50) - 1 = 200 - 1 = 199