Talk:Friday the 13th

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3 Friday the 13ths[edit]

A year with 3 Friday the 13ths can either be a leap year starting on Sunday (dominical letter AG), with the Friday the 13ths in January, April, and July; or a common year starting on Thursday (dominical letter D), with the Friday the 13ths in February, March, and November. GeoffreyT2000 (talk) 23:23, 5 March 2015 (UTC)

Why the mention of a particular airplane crash?[edit]

The section on the plane crash is hardly relevant to an entry about a superstition. It sounds like an attempt by a pious vandal to lend credence to the irrational fear of Friday the 13th. For balance and perspective, it would be reasonable to include references to all the plane crashes that did *not* occur on a Friday the 13th. But this is supposed to be an *encyclopedia* entry on a particular superstitious belief rather than a polemic or mystical pamphlet. The section on the famous plane crash does not belong here and should be removed, since it is as irrelevant to this entry as any other well-known event that happened to have occured on Friday the 13th. — Preceding unsigned comment added by (talk) 16:56, 13 March 2015 (UTC)

Julian calendar[edit]

The following table shows the Friday the 13ths in the Julian calendar. GeoffreyT2000 (talk) 15:59, 29 March 2015 (UTC)

Year mod 28 1st 2nd 3rd
0 February 13 August 13
1 May 13
2 January 13 October 13
3 April 13 July 13
4 June 13
5 February 13 March 13 November 13
6 August 13
7 May 13
8 January 13 April 13 July 13
9 September 13 December 13
10 June 13
11 February 13 March 13 November 13
12 May 13
13 January 13 October 13
14 April 13 July 13
15 September 13 December 13
16 March 13 November 13
17 August 13
18 May 13
19 January 13 October 13
20 September 13 December 13
21 June 13
22 February 13 March 13 November 13
23 August 13
24 October 13
25 April 13 July 13
26 September 13 December 13
27 June 13

As you can see, of those 28 years,

  • 12 have 1 Friday the 13th
  • 12 have 2 Friday the 13ths
  • 4 have 3 Friday the 13ths GeoffreyT2000 (talk) 17:45, 29 March 2015 (UTC)

Some More Interesting Facts About Years With Three Fridays the 13th[edit]

Three years before and after a year with three Fridays the 13th, those years will always have three Fridays the 13th as well. This also reminds me of one of Henry Dudeney's problems in his book "536 Puzzles and Curious Problems." Problem 528, "A Leap Year Puzzle," says "The month of February in 1928 contained five Wednesdays. There is, of course, nothing remarkable in this fact, but it will be found interesting to discover the last year prior to 1928 and the first year after 1928 that had five Wednesdays in February." Nothing remarkable, other than the fact that such a year will contain three Fridays the 13th. Finally, an American President whose second term commences on January 21 (because January 20 was a Sunday) will serve as President during three years with three Fridays the 13th. Ronald Reagan, for example, served as President during all three Fridays the 13th in 1981, 1984, and 1987. The previous year with three was 1970 and the next year with three was 1998. Neither Reagan's predecessor nor successor could have served as President in a year with three Fridays the 13th. — Preceding unsigned comment added by (talk) 16:15, 29 May 2015 (UTC)

The first statement is true when one starts with a leap year starting on Sunday. For common years starting on Thursday, three years before can be:
  • A leap year starting on Sunday (e.g. 2012/2015)
  • A common year starting on Sunday (e.g. 2006/2009 and 2023/2026)
  • A common year starting on Monday (twice every 400 years: 2198/2201 and 2300/2303)
and three years after can be:
  • A leap year starting on Sunday (e.g. 2009/2012)
  • A common year starting on Sunday (once every 400 years: 2099/2102)
  • A common year starting on Monday (e.g. 2015/2018 and 2026/2029)
GeoffreyT2000 (talk) 15:08, 10 August 2015 (UTC)