`(1 + 1/(1 xx 3)) xx (1 + 1/(2 xx 4)) xx (1 + 1/(3 xx 5)) xx ... xx (1 + 1/(2017 xx 2019))`
`= (1 + 1/3) xx (1 + 1/8) xx (1 + 1/15) xx ... xx (1 + 1/4072323)`
`= 4/3 xx 9/8 xx 16/15 xx ... xx 4072324/4072323`
`= (2 xx 2)/(1 xx 3) xx (3 xx 3)/(2 xx 4) xx (4 xx 4)/(3 xx 5) xx ... xx (2018 xx 2018)/(2017 xx 2019)`
`= (2 xx 2 xx 3 xx 3 xx 4 xx 4 xx ... xx 2018 xx 2018)/(1 xx 3 xx 2 xx 4 xx 3 xx 5 xx ... xx 2017 xx 2019)`
`= (2 xx 3 xx 4 xx ... xx 2018)/(1 xx 2 xx 3 xx ... xx 2017) xx (2 xx 3 xx 4 xx ... xx 2018)/(3 xx 4 xx 5 xx ... xx 2019)`
`= 2018/1 xx 2/2019`
`= 4036/2019`