Every Day Counts
Centred Square Prime Days
 
Age: 15,305 days
Date of birth
Your 32nd Centred Square Prime Day is on
Wednesday
when you will be
15,313 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:

Remind me, please


Next Prime Events
Day Age
Event
Days Ahead
Year Age
03 Jul 2025
15,307
2
41
09 Jul 2025
15,313
8
41
05 Oct 2025
15,401
96
42
24 Nov 2025
15,451
146
42
04 Aug 2027
16,069
764
43
01 Oct 2027
16,127
822
44
08 Mar 2029
16,651
1,346
45
16 Sep 2029
16,843
1,538
46
02 Jul 2031
17,497
2,192
47
16 May 2033
18,181
2,876
49
07 Sep 2036
19,391
4,086
53
07 Mar 2038
19,937
4,632
54
20 Jan 2062
28,657
13,352
78
20 Apr 2103
43,721
28,416
119
16 Sep 2116
48,619
33,314
133
11 Jan 2163
65,537
50,232
179
24 Feb 2258
100,279
84,974
274
16 Jun 2342
131,071
115,766
358
Ordinal
Day Age
Date
Age
1st
5
11 Aug 1983
0
2nd
13
19 Aug 1983
0
3rd
41
16 Sep 1983
0
4th
61
06 Oct 1983
0
5th
113
27 Nov 1983
0
6th
181
03 Feb 1984
0
7th
313
14 Jun 1984
0
8th
421
30 Sep 1984
1
9th
613
10 Apr 1985
1
10th
761
05 Sep 1985
2
11th
1,013
15 May 1986
2
12th
1,201
19 Nov 1986
3
13th
1,301
27 Feb 1987
3
14th
1,741
12 May 1988
4
15th
1,861
09 Sep 1988
5
16th
2,113
19 May 1989
5
17th
2,381
11 Feb 1990
6
18th
2,521
01 Jul 1990
6
19th
3,121
21 Feb 1992
8
20th
3,613
27 Jun 1993
9
21st
4,513
14 Dec 1995
12
22nd
5,101
24 Jul 1997
13
23rd
7,321
22 Aug 2003
20
24th
8,581
02 Feb 2007
23
25th
9,661
17 Jan 2010
26
26th
9,941
24 Oct 2010
27
27th
10,513
18 May 2012
28
28th
12,641
16 Mar 2018
34
29th
13,613
12 Nov 2020
37
30th
14,281
11 Sep 2022
39
31st
14,621
17 Aug 2023
40
32nd
15,313
09 Jul 2025
41
1
33rd
16,381
11 Jun 2028
44
34th
19,013
26 Aug 2035
52
35th
19,801
22 Oct 2037
54
36th
20,201
26 Nov 2038
55
37th
21,013
15 Feb 2041
57
38th
21,841
24 May 2043
59
39th
23,981
02 Apr 2049
65
40th
24,421
16 Jun 2050
66
41st
26,681
23 Aug 2056
73