A sequential time is one in which the numbers form a normal sequence, such as 1:02:03 4/5/06 (two minutes and three seconds past 1 AM on 4 May 2006 [or April 5, 2006 in the United States] or the same time and date in the "06" year of any other century). Short sequential times such as 1:23:45 or 12:34:56 appear every day. Larger sequential times rarely appear, such as 12:34:56 7/8/90, or 01:23:45 on 6/7/89. These times can be dependent on the date format being used; the month/day format will produce different results from the day/month format.
This term, however, is not limited to simple counting. Other sequences, such as the decimal numbers of the mathematical constants π (3/14/1592), e (2/7/1828), and the square root of two (1/4/1421) are also noted. Number sequences such as the Fibonacci sequence (1/1/2358) can also be found in time stamps.
These dates are particularly popular with couples getting married who are seeking unique wedding and anniversary dates. Dates with repeating numbers such as July 7, 2007 "7/7/07" are also popular.
Palindromic times can also be observed, e.g. 10:02:10 on 11/01/2001 (two minutes and ten seconds after 10 AM on 11 January 2001 in most of the world) was the first fully palindromic time sequence of the twenty-first century.
A sequential time occurred during Pi Day on 3/14/15 at 9:26:53.58979... following the sequence of pi to all digits.