#math trivia for #May8: #129 is another prime of the form 2^x+1. How many others will be encountered this year? — Burt Kaliski Jr. (@modulomathy) May 8, 2012 Nine day-numbers have the form 2^x+1:  2, 3, 5, 9, 17, 33, 65, 129, and 257.  Of these, six are prime:  2, 3, 5, 17, 129 and … Continue reading →