摘要： 描述 One afternoon as the cows were chewing their cud, Bessie said, "Let's have a contest to see who is the smartest cow. Here's the contest: we will choose a positive number N (no larger than 2,000,000) and whoever computes the rightmost non-zero digit of N factorial will be crowned the smartest cow." The other cows demurred, however, mooing, "We did that last year." "Oh," said Bessie, "but there's a catch. We're not necessarily going to use base 10. I know my hooves don't have that many digit 阅读全文