﻿﻿﻿ Every Day Counts

Centred Square Prime Days

Age: 14,291 days
Date of birth
Your 31st Centred Square Prime Day is on
Tuesday
when you will be
14,621 days old

A centred square prime is a centred square number that is prime.

Unlike regular square numbers, which are never prime, quite a few of the centred square numbers are prime.

Centred square numbers are of the form n2 + (n - 1)2

In elementary number theory, a centred square number is a centred figurate number that gives the number of dots in a square with a dot in the centre and all other dots surrounding the centre dot in successive square layers. That is, each centred square number equals the number of dots within a given city block distance of the centre dot on a regular square lattice. While centred square numbers, like figurate numbers in general, have few if any direct practical applications, they are sometimes studied in recreational mathematics for their elegant geometric and arithmetic properties.

The figures for the first four centred square numbers are shown below:

Next Prime Events
Day Age
Event
Year Age
06 Dec 2023
14,293
2
39
23 Jan 2024
14,341
50
39
19 Jul 2024
14,519
228
39
29 Oct 2024
14,621
330
40
16 Jun 2025
14,851
560
40
13 Dec 2028
16,127
1,836
44
21 May 2030
16,651
2,360
45
29 Nov 2030
16,843
2,552
46
13 Sep 2032
17,497
3,206
47
29 Jul 2034
18,181
3,890
49
20 Nov 2037
19,391
5,100
53
20 May 2039
19,937
5,646
54
04 Apr 2063
28,657
14,366
78
02 Jul 2104
43,721
29,430
119
29 Nov 2117
48,619
34,328
133
25 Mar 2164
65,537
51,246
179
09 May 2259
100,279
85,988
274
29 Aug 2343
131,071
116,780
358
Ordinal
Day Age
Date
Age
1st
5
23 Oct 1984
0
2nd
13
31 Oct 1984
0
3rd
41
28 Nov 1984
0
4th
61
18 Dec 1984
0
5th
113
08 Feb 1985
0
6th
181
17 Apr 1985
0
7th
313
27 Aug 1985
0
8th
421
13 Dec 1985
1
9th
613
23 Jun 1986
1
10th
761
18 Nov 1986
2
11th
1,013
28 Jul 1987
2
12th
1,201
01 Feb 1988
3
13th
1,301
11 May 1988
3
14th
1,741
25 Jul 1989
4
15th
1,861
22 Nov 1989
5
16th
2,113
01 Aug 1990
5
17th
2,381
26 Apr 1991
6
18th
2,521
13 Sep 1991
6
19th
3,121
05 May 1993
8
20th
3,613
09 Sep 1994
9
21st
4,513
25 Feb 1997
12
22nd
5,101
06 Oct 1998
13
23rd
7,321
03 Nov 2004
20
24th
8,581
16 Apr 2008
23
25th
9,661
01 Apr 2011
26
26th
9,941
06 Jan 2012
27
27th
10,513
31 Jul 2013
28
28th
12,641
29 May 2019
34
29th
13,613
25 Jan 2022
37
30th
14,281
24 Nov 2023
39
31st
14,621
29 Oct 2024
40
1
32nd
15,313
21 Sep 2026
41
33rd
16,381
24 Aug 2029
44
34th
19,013
07 Nov 2036
52
35th
19,801
04 Jan 2039
54
36th
20,201
08 Feb 2040
55
37th
21,013
30 Apr 2042
57
38th
21,841
05 Aug 2044
59
39th
23,981
15 Jun 2050
65
40th
24,421
29 Aug 2051
66
41st
26,681
05 Nov 2057
73