Consider all integer combinations of ab for 2 a 5 and 2 b 5:

22=4, 23=8, 24=16, 25=32

32=9, 33=27, 34=81, 35=243

42=16, 43=64, 44=256, 45=1024

52=25, 53=125, 54=625, 55=3125

If they are then placed in numerical order, with any repeats removed, we get the following sequence of 15 distinct terms:

4, 8, 9, 16, 25, 27, 32, 64, 81, 125, 243, 256, 625, 1024, 3125

How many distinct terms are in the sequence generated by ab for 2 a 100 and 2 b 100?

一行。遅いけど。 

p029 = length.nub$[a^b | a<-[2..100],b<-[2..100]]