This Primer is to accompany the 'Busy Beaver Turing Machines' film which can be viewed here: https://www.youtube.com/watch?v=CE8UhcyJS0I Professor Brailsford's code and further reading: http://bit.ly/busybeaver Turing and the Halting Problem: https://www.youtube.com/watch?v=macM_MtS_w4 Busy Beaver Turing Machines: https://www.youtube.com/watch?v=CE8UhcyJS0I Domino Addition – Numberphile: https://www.youtube.com/watch?v=lNuPy-r1GuQ Ackermann Follow Up: https://www.youtube.com/watch?v=uNACwX-O5lk 'Turing Machines Collection' Playlist:    • Turing Machines Collection - Computer...   “The Most Difficult Program to Compute?” (Original Ackermann Film): https://www.youtube.com/watch?v=i7sm9dzFtEI http://www.facebook.com/computerphile https://twitter.com/computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: http://bit.ly/nottscomputer Computerphile is a sister project to Brady Haran's Numberphile. See the full list of Brady's video projects at: http://bit.ly/bradychannels