What is Graham's Number? (feat Ron Graham)

Ron Graham explains the number which takes his name...
See our other Graham's Number videos: http://bit.ly/G_Number
More Ron Graham Videos: http://bit.ly/Ron_Graham

Graham's Number (Numberphile T-Shirt): http://bit.ly/Grahams_T-Shirt
See him discuss how big it is: http://youtu.be/GuigptwlVHo
Extra footage here: http://youtu.be/rGWuimr5CGQ
And our original Graham's Number video: http://youtu.be/XTeJ64KD5cg