7 is the last single digit prime..........9 is the last single digit non prime.......9 + 7 = 16.......like the gold ratio.........................like 97...........the last prime under 100..................100.......is the 1st number in triple digits.......1st in triple digits.......a 1 and a 3.........like 13.......................from 7 to 11...........there is a distance of 4.........11 - 7 = 4.........but there are 3 integers between them..............8, 9, 10...................whose sum is 27...........like e...........................a distance of 4..........but 3 integers in between.............one gap.....a 1, 3, and a 4.........like pi....................the 1st 3 digits.......3.14.................e = 2.71.......the 1st 3.........added......................3.14 + 2.71 = 5.85...........from 8..................forwards and backwards.......adding................two 13s.............5 + 8 = 13..........................8 + 5 = 13.............reflex. sym.......and two gold ratios..........8/5 = 1.6.......................