Every Day Counts
Centred Triangular Prime Days
 
Age: 20,131 days
Date of birth
Your 28th Centred Triangular Prime Day is on
Sunday
when you will be
20,359 days old

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

Centred triangular numbers are of the form (3n2 + 3n + 2) / 2

A centred triangular number is a centred figurate number that represents a triangle with a dot in the centre and all other dots surrounding the centre in successive triangular layers.

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

Remind me, please


Next Prime Events
Day Age
Event
Days Ahead
Year Age
27 Jan 2025
20,143
12
55
26 Mar 2025
20,201
70
55
29 Aug 2025
20,357
226
55
31 Aug 2025
20,359
228
55
04 May 2029
21,701
1,570
59
20 May 2031
22,447
2,316
61
20 May 2048
28,657
8,526
78
05 May 2052
30,103
9,972
82
09 Oct 2071
37,199
17,068
101
15 Sep 2077
39,367
19,236
107
17 Aug 2089
43,721
23,590
119
15 Jan 2103
48,619
28,488
133
11 May 2149
65,537
45,406
179
24 Jun 2244
100,279
80,148
274
12 Jan 2268
108,881
88,750
298
14 Oct 2328
131,071
110,940
358
05 Feb 7787
2,124,679
2,104,548
5817
Ordinal
Day Age
Date
Age
1st
19
23 Dec 1969
0
2nd
31
04 Jan 1970
0
3rd
109
23 Mar 1970
0
4th
199
21 Jun 1970
0
5th
409
17 Jan 1971
1
6th
571
28 Jun 1971
1
7th
631
27 Aug 1971
1
8th
829
12 Mar 1972
2
9th
1,489
01 Jan 1974
4
10th
1,999
26 May 1975
5
11th
2,341
02 May 1976
6
12th
2,971
22 Jan 1978
8
13th
3,529
03 Aug 1979
9
14th
4,621
30 Jul 1982
12
15th
4,789
14 Jan 1983
13
16th
7,039
13 Mar 1989
19
17th
7,669
03 Dec 1990
20
18th
8,779
17 Dec 1993
24
19th
9,721
16 Jul 1996
26
20th
10,459
24 Jul 1998
28
21st
10,711
02 Apr 1999
29
22nd
13,681
20 May 2007
37
23rd
14,851
02 Aug 2010
40
24th
16,069
02 Dec 2013
43
25th
16,381
10 Oct 2014
44
26th
17,659
10 Apr 2018
48
27th
20,011
17 Sep 2024
54
28th
20,359
31 Aug 2025
55
1
29th
23,251
01 Aug 2033
63
30th
25,939
10 Dec 2040
71
31st
27,541
30 Apr 2045
75
32nd
29,191
05 Nov 2049
79
33rd
29,611
30 Dec 2050
81
34th
31,321
05 Sep 2055
85
35th
34,429
09 Mar 2064
94
36th
36,739
06 Jul 2070
100
37th
40,099
17 Sep 2079
109
38th
40,591
21 Jan 2081
111
39th
42,589
12 Jul 2086
116