Every Day Counts
Centred Triangular Prime Days
 
Age: 16,368 days
Date of birth
Your 25th Centred Triangular Prime Day is on
Tuesday
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
04 Dec 2025
16,369
tomorrow
44
16 Dec 2025
16,381
13
44
16 Dec 2025
16,381
13
44
16 Dec 2025
16,381
13
44
14 Jun 2026
16,561
193
45
12 Sep 2026
16,651
283
45
23 Mar 2027
16,843
475
46
05 Jan 2029
17,497
1,129
47
20 Nov 2030
18,181
1,813
49
14 Mar 2034
19,391
3,023
53
11 Sep 2035
19,937
3,569
54
27 Jul 2059
28,657
12,289
78
24 Oct 2100
43,721
27,353
119
23 Mar 2114
48,619
32,251
133
17 Jul 2160
65,537
49,169
179
31 Aug 2255
100,279
83,911
274
21 Dec 2339
131,071
114,703
358
Ordinal
Day Age
Date
Age
1st
19
28 Feb 1981
0
2nd
31
12 Mar 1981
0
3rd
109
29 May 1981
0
4th
199
27 Aug 1981
0
5th
409
25 Mar 1982
1
6th
571
03 Sep 1982
1
7th
631
02 Nov 1982
1
8th
829
19 May 1983
2
9th
1,489
09 Mar 1985
4
10th
1,999
01 Aug 1986
5
11th
2,341
09 Jul 1987
6
12th
2,971
30 Mar 1989
8
13th
3,529
09 Oct 1990
9
14th
4,621
05 Oct 1993
12
15th
4,789
22 Mar 1994
13
16th
7,039
19 May 2000
19
17th
7,669
08 Feb 2002
20
18th
8,779
22 Feb 2005
24
19th
9,721
22 Sep 2007
26
20th
10,459
29 Sep 2009
28
21st
10,711
08 Jun 2010
29
22nd
13,681
26 Jul 2018
37
23rd
14,851
08 Oct 2021
40
24th
16,069
07 Feb 2025
43
25th
16,381
16 Dec 2025
44
1
26th
17,659
16 Jun 2029
48
27th
20,011
24 Nov 2035
54
28th
20,359
06 Nov 2036
55
29th
23,251
07 Oct 2044
63
30th
25,939
16 Feb 2052
71
31st
27,541
06 Jul 2056
75
32nd
29,191
11 Jan 2061
79
33rd
29,611
07 Mar 2062
81
34th
31,321
11 Nov 2066
85
35th
34,429
16 May 2075
94
36th
36,739
11 Sep 2081
100
37th
40,099
23 Nov 2090
109
38th
40,591
29 Mar 2092
111
39th
42,589
17 Sep 2097
116