Hint: 3+6+9+12=3(1+2+3+4)NameIsUnique said:I know n(n+1)/2 solves from 1... n by 1's
Is there a formula where you can add up by 3's?
Example: 3 + 6 + 9 + 12 ... n
The summation formula for adding by 3's is n(2n+1)/3.
The formula works by multiplying the value of n by 2, adding 1 to the result, and then dividing the final value by 3.
Yes, the formula can be used for any positive integer value of n.
The formula can be used in situations where a series of numbers needs to be added by 3's, such as calculating the total cost of items in a store where each item costs $3.
Yes, there are formulas for adding by different intervals, such as the summation formula for adding by 2's (n(n+1)/2) or the formula for adding by 5's (n(3n+5)/2).