1. Andy slammed the letter down on his desk angrily. "Still no payment on my claim," he said. "Now they want the serial number." "Do you have a note of it?" asked Mary. "Of course, but I'll give it this way." Her husband chuckled. "It's just one less than twice the square of its last three digits." What was the number?

Serial number 1739557

Serial number 1757395

Serial number 1755937