﻿﻿﻿ Every Day Counts

Centred Square Prime Days

Age: 14,282 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
15 Dec 2021
14,293
11
39
01 Feb 2022
14,341
59
39
29 Jul 2022
14,519
237
39
08 Nov 2022
14,621
339
40
26 Jun 2023
14,851
569
40
23 Dec 2026
16,127
1,845
44
30 May 2028
16,651
2,369
45
08 Dec 2028
16,843
2,561
46
23 Sep 2030
17,497
3,215
47
07 Aug 2032
18,181
3,899
49
30 Nov 2035
19,391
5,109
53
29 May 2037
19,937
5,655
54
13 Apr 2061
28,657
14,375
78
12 Jul 2102
43,721
29,439
119
09 Dec 2115
48,619
34,337
133
04 Apr 2162
65,537
51,255
179
18 May 2257
100,279
85,997
274
07 Sep 2341
131,071
116,789
358
Ordinal
Day Age
Date
Age
1st
5
02 Nov 1982
0
2nd
13
10 Nov 1982
0
3rd
41
08 Dec 1982
0
4th
61
28 Dec 1982
0
5th
113
18 Feb 1983
0
6th
181
27 Apr 1983
0
7th
313
06 Sep 1983
0
8th
421
23 Dec 1983
1
9th
613
02 Jul 1984
1
10th
761
27 Nov 1984
2
11th
1,013
06 Aug 1985
2
12th
1,201
10 Feb 1986
3
13th
1,301
21 May 1986
3
14th
1,741
04 Aug 1987
4
15th
1,861
02 Dec 1987
5
16th
2,113
10 Aug 1988
5
17th
2,381
05 May 1989
6
18th
2,521
22 Sep 1989
6
19th
3,121
15 May 1991
8
20th
3,613
18 Sep 1992
9
21st
4,513
07 Mar 1995
12
22nd
5,101
15 Oct 1996
13
23rd
7,321
13 Nov 2002
20
24th
8,581
26 Apr 2006
23
25th
9,661
10 Apr 2009
26
26th
9,941
15 Jan 2010
27
27th
10,513
10 Aug 2011
28
28th
12,641
07 Jun 2017
34
29th
13,613
04 Feb 2020
37
30th
14,281
03 Dec 2021
39
31st
14,621
08 Nov 2022
40
1
32nd
15,313
30 Sep 2024
41
33rd
16,381
03 Sep 2027
44
34th
19,013
17 Nov 2034
52
35th
19,801
13 Jan 2037
54
36th
20,201
17 Feb 2038
55
37th
21,013
09 May 2040
57
38th
21,841
15 Aug 2042
59
39th
23,981
24 Jun 2048
65
40th
24,421
07 Sep 2049
66
41st
26,681
15 Nov 2055
73