3 $ 2 = 15
7 $ 4 = 311
62 $ 13 = 4975
51 $ 43 = ???
Harder:
15 $ 11 = 104
18 $ 7 = 275
62 $ 13 = 3675
24 $ 1 = ???
Difficult:
31 $ 41 = 592
27 $ 18 = 281
16 $ 180 = 339
33 $ 21 = ???
A $ B denotes a function of A and B, unchanged within a section.
