Every Day Counts
Centred Triangular Prime Days
 
Age: 16,362 days
Date of birth
Your 25th Centred Triangular Prime Day is on
Wednesday
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
28 Mar 2026
16,363
tomorrow
44
15 Apr 2026
16,381
19
44
15 Apr 2026
16,381
19
44
15 Apr 2026
16,381
19
44
12 Oct 2026
16,561
199
45
10 Jan 2027
16,651
289
45
21 Jul 2027
16,843
481
46
05 May 2029
17,497
1,135
47
20 Mar 2031
18,181
1,819
49
12 Jul 2034
19,391
3,029
53
09 Jan 2036
19,937
3,575
54
24 Nov 2059
28,657
12,295
78
21 Feb 2101
43,721
27,359
119
21 Jul 2114
48,619
32,257
133
14 Nov 2160
65,537
49,175
179
29 Dec 2255
100,279
83,917
274
19 Apr 2340
131,071
114,709
358
Ordinal
Day Age
Date
Age
1st
19
28 Jun 1981
0
2nd
31
10 Jul 1981
0
3rd
109
26 Sep 1981
0
4th
199
25 Dec 1981
0
5th
409
23 Jul 1982
1
6th
571
01 Jan 1983
1
7th
631
02 Mar 1983
1
8th
829
16 Sep 1983
2
9th
1,489
07 Jul 1985
4
10th
1,999
29 Nov 1986
5
11th
2,341
06 Nov 1987
6
12th
2,971
28 Jul 1989
8
13th
3,529
06 Feb 1991
9
14th
4,621
02 Feb 1994
12
15th
4,789
20 Jul 1994
13
16th
7,039
16 Sep 2000
19
17th
7,669
08 Jun 2002
20
18th
8,779
22 Jun 2005
24
19th
9,721
20 Jan 2008
26
20th
10,459
27 Jan 2010
28
21st
10,711
06 Oct 2010
29
22nd
13,681
23 Nov 2018
37
23rd
14,851
05 Feb 2022
40
24th
16,069
07 Jun 2025
43
25th
16,381
15 Apr 2026
44
1
26th
17,659
14 Oct 2029
48
27th
20,011
23 Mar 2036
54
28th
20,359
06 Mar 2037
55
29th
23,251
04 Feb 2045
63
30th
25,939
15 Jun 2052
71
31st
27,541
03 Nov 2056
75
32nd
29,191
11 May 2061
79
33rd
29,611
05 Jul 2062
81
34th
31,321
11 Mar 2067
85
35th
34,429
13 Sep 2075
94
36th
36,739
09 Jan 2082
100
37th
40,099
23 Mar 2091
109
38th
40,591
27 Jul 2092
111
39th
42,589
15 Jan 2098
116