# Explanation of Terms on the Page Displaying a Single Prime

**Code name**- Each proof-code represents the method by which one (or more) primes were proven to be prime. These
proof-codes often involve multiple persons, programs and projects. To make them easier to refer to and print,
each is given a short code name.

**Persons**- The number of 'persons' involved in this proof. Persons split the credit for primes, whereas programs
and projects do not.

**Score**- A measure of how difficult it is to find primes of this size:
log((log
*n*)^{3}log log*n*). See the bottom of the Top 20 by Score page for an explanation. The normalized score is this score without the final (natural) log, divided by the same for the 5000th prime. See the bottom of the page Top 20 by Normalized Score for more information about normalized scores.

**Entrance rank**- As new primes are added, the rank of any given prime slowly drops. The 'entrance rank' is the rank the prime
had when it was first added--so it is its highest rank. This rank is less reliable on primes submitted before 2000
because the submission time was less granular. In fact, for some primes submitted before 1 January 1997 we only know
what year they were submitted. The mean, minimum and maximum given for the entrance rank are just for the active
primes (the primes still on the list).

**Removed (date)**- Primes eventually get pushed off the list by the new primes being added. For primes that have been pushed off, and have no comments, 'removed' is the date/time at which they were pushed off. This feature has not yet been implemented for primes with comments because that is much more difficult to do.

Printed from the PrimePages <primes.utm.edu> © Chris Caldwell.