
COMMENTS

a(7) >= 192.  Rick L. Shepherd, May 08 2003
From Lars Blomberg, Apr 08 2018: (Start)
The terms a(6)a(9) have been computed with these rules:
Division by 0 or exponentiation 0^0 is not allowed.
Concatenation where at least one operand is a fraction or where the second operand is negative are skipped.
Exponentations yielding > 100000 digits or with exponent > 32bit signed integer are skipped. (End)


EXAMPLE

With three 3's one can form 1=(3/3)^3, 2=33/3, 3=3+33, 4=3+3/3, but not 5, so a(3)=5.
With four 4's one can get 1=44/44, 2=4/4+4/4, 3=4(4/4)^4, 4=4+(44)^4, 5=4+(4/4)^4, 6=(4+4)/4+4, 7=44/44, 8=4+4+44, 9=4+4+4/4, 10=(444)/4, 11=(4/4)  (4/4), 12=(44+4)/4, but not 13, so a(4)=13 ( denotes concatenation).
With five 5's one can get 1 = (((5  5)  5)^(5  5)), 2 = (((5  5)  5) / (5 * 5)), 3 = (((5 * 5) + 5) / (5 + 5)), 4 = (((5 / 5) * 5)  (5 / 5)), 5 = (((5  5) * 5) / (5  5)), 6 = (((5  5) + 5) / (5 + 5)),
7 = (((5 / 5) + 5) + (5 / 5)), 8 = (( 5 + 5)  ((5 + 5) / 5)), 9 = (( 5 + 5)  ((5 / 5)^5)), 10 = (((5  5) / 5)  (5 / 5)), 11 = (((5  5) / 5)^(5 / 5)), 12 = (((5  5) / 5) + (5 / 5)),
13 = (((5  5) + (5 + 5)) / 5), 14 = (((5 / 5)  5)  (5 / 5)), 15 = (((5 / 5)  5)^(5 / 5)), 16 = (((5 / 5)  5) + (5 / 5)), 17 = (( 5  (5^5)) / (5^5)), but not 18, so a(5) = 18.
