This bestselling novelist’s giveaway contest celebrates the beauty of prime numbers
When Robin Sloan wants to give away free copies of his books, he—like most authors—asks fans to participate in a contest. But his contests have an unusual twist: They double as a celebration of prime numbers. Sloan’s 2012 debut novel, Mr. Penumbra’s 24-Hour Bookstore, was a bestselling mystery involving an ancient book cult, Google, and…