In order to solve this problem, We need to substitute the first four numbers (1,2,3,4) for n. After this we calculate: First item: a1= -2*1 + 4=-2+4=2 Second item: a2= -2*2 + 4
=-4+4=0 Third item: a3= -2*3 + 4
=-6+4=-2 Forth item: a4= -2*4 + 4
=-8+4=-4