(2+1)({2}^{2}+1)({2}^{4}+1)({2}^{8}+1).({2}^{64}+1)+1
=(2-1)(2+1)({2}^{2}+1)({2}^{4}+1)({2}^{8}+1).({2}^{64}+1)+1
={2^2-1}({2}^{2}+1)({2}^{4}+1)({2}^{8}+1).({2}^{64}+1)+1
=({2}^{4}-1)({2}^{4}+1)({2}^{8}+1).({2}^{64}+1)+1
=({2}^{8}-1)({2}^{8}+1).({2}^{64}+1)+1
=({2}^{16}-1).({2}^{64}+1)+1
………………………………………………
=({2}^{128}-1)+1
={2}^{128}