﻿﻿﻿ Every Day Counts

Centred Square Prime Days

Age: 13,612 days
Date of birth
Your 29th Centred Square Prime Day is on
Tuesday
when you will be
13,613 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
05 Dec 2023
13,613
tomorrow
37
05 Dec 2023
13,613
tomorrow
37
30 Jan 2024
13,669
57
37
09 Feb 2024
13,679
67
37
11 Feb 2024
13,681
69
37
10 Jul 2024
13,831
219
37
11 Jul 2025
14,197
585
38
29 May 2026
14,519
907
39
23 Oct 2030
16,127
2,515
44
08 Oct 2032
16,843
3,231
46
24 Jul 2034
17,497
3,885
47
07 Jun 2036
18,181
4,569
49
30 Sep 2039
19,391
5,779
53
29 Mar 2041
19,937
6,325
54
11 Feb 2065
28,657
15,045
78
09 Oct 2119
48,619
35,007
133
02 Feb 2166
65,537
51,925
179
08 Jul 2345
131,071
117,459
358
Ordinal
Day Age
Date
Age
1st
5
02 Sep 1986
0
2nd
13
10 Sep 1986
0
3rd
41
08 Oct 1986
0
4th
61
28 Oct 1986
0
5th
113
19 Dec 1986
0
6th
181
25 Feb 1987
0
7th
313
07 Jul 1987
0
8th
421
23 Oct 1987
1
9th
613
02 May 1988
1
10th
761
27 Sep 1988
2
11th
1,013
06 Jun 1989
2
12th
1,201
11 Dec 1989
3
13th
1,301
21 Mar 1990
3
14th
1,741
04 Jun 1991
4
15th
1,861
02 Oct 1991
5
16th
2,113
10 Jun 1992
5
17th
2,381
05 Mar 1993
6
18th
2,521
23 Jul 1993
6
19th
3,121
15 Mar 1995
8
20th
3,613
19 Jul 1996
9
21st
4,513
05 Jan 1999
12
22nd
5,101
15 Aug 2000
13
23rd
7,321
13 Sep 2006
20
24th
8,581
24 Feb 2010
23
25th
9,661
08 Feb 2013
26
26th
9,941
15 Nov 2013
27
27th
10,513
10 Jun 2015
28
28th
12,641
07 Apr 2021
34
29th
13,613
05 Dec 2023
37
1
30th
14,281
03 Oct 2025
39
31st
14,621
08 Sep 2026
40
32nd
15,313
31 Jul 2028
41
33rd
16,381
04 Jul 2031
44
34th
19,013
17 Sep 2038
52
35th
19,801
13 Nov 2040
54
36th
20,201
18 Dec 2041
55
37th
21,013
09 Mar 2044
57
38th
21,841
15 Jun 2046
59
39th
23,981
24 Apr 2052
65
40th
24,421
08 Jul 2053
66
41st
26,681
15 Sep 2059
73