what is the formula to the sequence 0,4,8,12,16...

Question

 i need the formula to the sequence

Answer 1

a_n=4n, n=0,1,2,... 

or 

a_n=4(n-1), n=1,2,...

a₁=0,

a₂=4,

a₃=8,

...

Answer 2

The next number is just 4 plus the previous number.  The sequence is

 

0, 0 + (1)4, 0 + 2(4), 0 + 3(4), 0 + 4(4), ... , 0 + 4n, ...

 

a₀ = 0

a_n = a₀ + 4n,

for n = 1, 2, 3, ...