What the the next number in the series 15, 11, 9, 5, 3, 1, ?

Question

On behalf of Sture Sjöstedt

Answer 1

-3
3X5, 3X3 + 2, 3X3, 3X1+ 2, 3X1, (3X-1 ) + 2, (3x-1)

Comments

But then it would be 3x minus 1

Answer 2

15, 11, 9, 5, 3, 1,=0