Every Day Counts
Centred Triangular Prime Days
 
Age: 16,366 days
Date of birth
Your 25th Centred Triangular Prime Day is on
Sunday
when you will be
16,381 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
21 Jul 2026
16,369
3
44
02 Aug 2026
16,381
15
44
02 Aug 2026
16,381
15
44
02 Aug 2026
16,381
15
44
29 Jan 2027
16,561
195
45
29 Apr 2027
16,651
285
45
07 Nov 2027
16,843
477
46
22 Aug 2029
17,497
1,131
47
07 Jul 2031
18,181
1,815
49
29 Oct 2034
19,391
3,025
53
27 Apr 2036
19,937
3,571
54
12 Mar 2060
28,657
12,291
78
10 Jun 2101
43,721
27,355
119
07 Nov 2114
48,619
32,253
133
03 Mar 2161
65,537
49,171
179
16 Apr 2256
100,279
83,913
274
06 Aug 2340
131,071
114,705
358
Ordinal
Day Age
Date
Age
1st
19
15 Oct 1981
0
2nd
31
27 Oct 1981
0
3rd
109
13 Jan 1982
0
4th
199
13 Apr 1982
0
5th
409
09 Nov 1982
1
6th
571
20 Apr 1983
1
7th
631
19 Jun 1983
1
8th
829
03 Jan 1984
2
9th
1,489
24 Oct 1985
4
10th
1,999
18 Mar 1987
5
11th
2,341
23 Feb 1988
6
12th
2,971
14 Nov 1989
8
13th
3,529
26 May 1991
9
14th
4,621
22 May 1994
12
15th
4,789
06 Nov 1994
13
16th
7,039
03 Jan 2001
19
17th
7,669
25 Sep 2002
20
18th
8,779
09 Oct 2005
24
19th
9,721
08 May 2008
26
20th
10,459
16 May 2010
28
21st
10,711
23 Jan 2011
29
22nd
13,681
12 Mar 2019
37
23rd
14,851
25 May 2022
40
24th
16,069
24 Sep 2025
43
25th
16,381
02 Aug 2026
44
1
26th
17,659
31 Jan 2030
48
27th
20,011
10 Jul 2036
54
28th
20,359
23 Jun 2037
55
29th
23,251
24 May 2045
63
30th
25,939
02 Oct 2052
71
31st
27,541
20 Feb 2057
75
32nd
29,191
28 Aug 2061
79
33rd
29,611
22 Oct 2062
81
34th
31,321
28 Jun 2067
85
35th
34,429
31 Dec 2075
94
36th
36,739
28 Apr 2082
100
37th
40,099
10 Jul 2091
109
38th
40,591
13 Nov 2092
111
39th
42,589
04 May 2098
116