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The five triangular numbers that follow 21 are 28, 36, 45, 55, and 66.
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Which triangular numbers are prime numbers?
3 is a triangular number that is also prime.Here is a list of some of the first few triangular numbers:0, 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171, 190, 210, 231, 253, 276, 300, 325, 351, 378, 406, 435, 465, 496, 528, 561, 595, 630, 666, 703, 741, 780, 820, 861, 903, 946, 990, 1035, 1081, 1128, 1176, 1225, 1275
Why are the numbers called triangular numbers?
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171, 190, 210, 231, 253, 276, 300, 325, 351, 378, 406, 435,
What is the prime numbers between 21 and 33?
there are 3 prime numbers in between 21 and 33... they are 23,29, 31.
What are the prime numbers from 21 to 40?
The prime numbers from 21 to 40 are 23, 29, 31, and 37.
How many composite numbers are there from 101 to 200?
Out of those 100 numbers, 21 of them are prime numbers, so the remaining (100 - 21) = 79 are composite.
Smaller of two triangular numbers whose sum and difference are also triangular numbers?
The answer would be 15 and 21. The triangular numbers are 1,3,6,10,15,21,28,36,45,55,66,78. 15 plus 21 is 36 which is on the list. 21 minus 15 is 6 and that is on the list as well.
Is 21 a triangular number?
Yes, the number 21 is indeed a triangular number. Other triangular numbers are 6,10, and 15.
What is the algebraic expression of 1 3 6 10 15 21?
Triangular numbers follow the form (n^2+n)/2
How can sixth triangular number be 21?
Because it is ! The first 10 triangular numbers are... 1,3,6,10,15,21,28,36,45 & 55
What triangular numbers are equal to the sum of two other triangular numbers?
Thre are infinitely many solutions. The smalest set with two different triangular number adding to another is 6 + 15 = 21
Is 8 triangular number?
No. The first few triangular numbers are 1, 3, 6, 10, 15, 21, 28, ...
What are the next four triangular numbers after 15?
21, 28, 36, 45
What are the triangular numbers between 1 and 66?
The triangular numbers between 1 and 66 are: 3, 6, 10, 15, 21, 28, 36, 45 and 55.
Is 32 a triangular number?
32 is not a triangular number. The first few triangular numbers are 1, 3, 6, 10, 15, 21, 28, 36, 45, ...
What are the first twelve triangular numbers?
The first twelve triangular numbers are: 1 3 6 10 15 21 28 36 45 55 66 78
What are the First six triangular numbers?
1, 3, 6, 10, 15, 21
Is 23 a triangle number?
No, 23 is not a triangular number. Here are a few examples of triangular numbers: 21, 28, 55, 45, 78 and 91.
