Question 43315
The n-th term: {{{a[n]=n^2-n}}}


First term: {{{a[1]=1^2-1}}} = 1 - 1 = 0
Second term: {{{a[2]=2^2-2}}} = 4 - 2 = 2
Third term: {{{a[3]=3^2-3}}} = 9 - 3 = 6
Fourth term: {{{a[4]=4^2-4}}} = 16 - 4 = 12
Fifth term: {{{a[5]=5^2-5}}} = 25 - 5 = 20


Hence the first five terms are 0, 2, 6, 12, 20.
Hence (a) is correct.