Every Day Counts
Centred Square Prime Days
 
Age: 19,013 days
Date of birth

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
23 Jan 2021
19,013
today
52
23 Jan 2021
19,013
today
52
05 Feb 2022
19,391
378
53
05 Feb 2022
19,391
378
53
09 Mar 2022
19,423
410
53
27 Mar 2022
19,441
428
53
05 Aug 2023
19,937
924
54
18 Oct 2023
20,011
998
54
20 Jun 2047
28,657
9,644
78
15 Oct 2076
39,367
20,354
107
16 Sep 2088
43,721
24,708
119
14 Feb 2102
48,619
29,606
133
10 Jun 2148
65,537
46,524
179
25 Jul 2243
100,279
81,266
274
11 Feb 2267
108,881
89,868
298
14 Nov 2327
131,071
112,058
358
07 Mar 7786
2,124,679
2,105,666
5817
Ordinal
Day Age
Date
Age
1st
5
08 Jan 1969
0
2nd
13
16 Jan 1969
0
3rd
41
13 Feb 1969
0
4th
61
05 Mar 1969
0
5th
113
26 Apr 1969
0
6th
181
03 Jul 1969
0
7th
313
12 Nov 1969
0
8th
421
28 Feb 1970
1
9th
613
08 Sep 1970
1
10th
761
03 Feb 1971
2
11th
1,013
13 Oct 1971
2
12th
1,201
18 Apr 1972
3
13th
1,301
27 Jul 1972
3
14th
1,741
10 Oct 1973
4
15th
1,861
07 Feb 1974
5
16th
2,113
17 Oct 1974
5
17th
2,381
12 Jul 1975
6
18th
2,521
29 Nov 1975
6
19th
3,121
21 Jul 1977
8
20th
3,613
25 Nov 1978
9
21st
4,513
13 May 1981
12
22nd
5,101
22 Dec 1982
13
23rd
7,321
19 Jan 1989
20
24th
8,581
02 Jul 1992
23
25th
9,661
17 Jun 1995
26
26th
9,941
23 Mar 1996
27
27th
10,513
16 Oct 1997
28
28th
12,641
14 Aug 2003
34
29th
13,613
12 Apr 2006
37
30th
14,281
09 Feb 2008
39
31st
14,621
14 Jan 2009
40
32nd
15,313
07 Dec 2010
41
33rd
16,381
09 Nov 2013
44
34th
19,013
23 Jan 2021
52
1
35th
19,801
22 Mar 2023
54
36th
20,201
25 Apr 2024
55
37th
21,013
16 Jul 2026
57
38th
21,841
21 Oct 2028
59
39th
23,981
31 Aug 2034
65
40th
24,421
14 Nov 2035
66
41st
26,681
21 Jan 2042
73