what's the relation between these numbers 1,2,4,9,16,25,36,...
Think "squares."
http://www.mathsisfun.com/square-root.html
The subject is maths.
These are positive integers n such that the sum of the divisors of n, excluding 1, is a multiple of the number of divisors of n.
so the next numbers in the sequence are
64, 81, 100, 121, 289,
As examples
The 9 divisors of 36 are {1,2,3,4,6,9,12,18,36}, giving sum (1+2+3=4+6+9+12+18+36)-1=90 which is a multiple of 9. Thus 36 is a term of the sequence.
The 3 divisors of 25 are
{1,5,25} giving a sum (1+5+25)-1=30 which is a multiple of 3. Thus 25 is a term of the sequence.
it's not square cuz i want the relation btw these numbers 1,2,4,9,16,25,36,.. NOT btw these numbers 1,4,9,16,25,...
Agreed it is not squares. It is the sequence as I described above.
The relation between these numbers can be deduced by observing the pattern. Let's break it down step by step:
1 squared is equal to 1.
2 squared is equal to 4.
3 squared is equal to 9.
4 squared is equal to 16.
5 squared is equal to 25.
6 squared is equal to 36.
By looking at these numbers, we can see that each number in the sequence is the square of its corresponding position. In other words, the nth number in the sequence is equal to n squared.
To find any number in this sequence, you simply need to square the corresponding position number. For example, the tenth number in the sequence would be 10 squared, which equals 100.
Therefore, the relation between these numbers is that each number in the sequence is the square of its corresponding position.