It’s a beautiful day (Spring is here! Spring is here!) and time to go to the carnival! The Carnival of Mathematics #31 is hosted by Recursivity this week, and blog author Jeffrey Shallit notes that not only is 31 a Mersenne prime (because it’s of the form 2^{prime}-1, in this case 2^{5}-1), but so is 2^{31}-1. (The pattern ends there, however, as he explains that 2^{(231-1)}-1 is not a prime at all.)

Recursivity is a blog about mathematics, science, politics, music, and religion. I especially enjoyed this post on math mistakes last month (since that’s a running category in our own blog). Bonus points for having a Blog name that my spellcheck doesn’t recognize [HAH! It doesn’t recognize the word “spellcheck” either! ] [Or “HAH!”].