On the other hand , if c is equal to the square root of -1 , also known as i , then the sequence is 0 , i , ( â ' 1 + i ) , â ' i , ( â ' 1 + i ) , â ' iâ , which does not go to infinity and so i belongs to the Mandelbrot set . As this sequence is unbounded , 1 is not an element of the Mandelbrot set . On the other hand , c = i ( where i is defined as i2 = 1 ) gives the sequence 0 , i , ( 1 + i ) , i , ( 1 + i ) , i , ... , which is bounded and so i belongs to the Mandelbrot set .