python (a?)^na^n on a^n

from timeit import Timer

for n in range(30) :
    t = Timer ('re.match("a?"*'+str(n)+' + "a"*'+str(n)+' , "a"*'+str(n)+' )', "import re")
    print("n = " + str(n) + "\ttime = " + str(t.timeit(1)))