Thirteen is the fourth episode of the fourth season. It was released on 19 October 2007.
Charlie is uncomfortable when the team has to employ a numerologist (which he views as superstition at best) to solve the current case, one which has religious overtones.
The title refers to the various beliefs surrounding the 'baker's dozen', up to and including triskaidekaphobia.
Guest star Sharif Atkins (Clay Porter) went on to Star in White Collar, on which Diane Farr (Megan Reeves) later guest started in turn. Also, both Sharif Atkins and Dylan Bruno (Colby Granger) later guest starred on SEAL Team.
During the beginning of the episode when Alan first walks in, Don calls his father by his own first name. Not sure if it's a real goof or not, but it would be weird calling ones father by his own name when normally Don calls Alan by dad.
When Charlie, Amita, Megan, and Dr.Trowbridge are in the FBI office discussing the number 888 and Dr. Trowbridge lists the numbers associated with the Greek spelling of "Jesus", she both writes them on the board and verbalizes them. She lists "8, 200, 70, 400, 200" out loud, which Amita says total "888", despite those numbers adding up to only 878. However, Dr. Trowbridge writes the correct numbers on the board (10, 8, 200, 70, 400, 200) which accurately add up to 888.
[This appears on the beginning of the episode] 6 days of creation 10 commandments 14 stations of the cross 1 Word of God