a(7) is a 77-digit number with factorization: 2^35 3^20 5^9 7^3 11 13^2 17 19 23 29 31 37^2 41 61 67 71 73 109 137 409 521 547 1093 36809 368089.
An upper bound for a(8) is a 165-digit number that can be found on given link where line begins with 25/3.