1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20 + 21 + 22 + 23 + 24 + 25 + 26 + 27 + 28 + 29 + 30
five thousand and fifty
In a string of numbers: 3, 6, 11, 18, 27 Which number is 578 in the string?
The general formula is: an = n ^ 2 + 2
For example: 3 = 1 ^ 2 + 2
6 = 2^2 + 2
11 = 3^2 + 2
.
578 = 24^2 + 2
So 578 is the 24th number in the string
One third, one sixth, one eleventh, one eighteenth, (), one 38th
Be specific
The law of denominator 3,5,7,9,11 odd difference
Looking for rules: 3, 9, 27, 81 What is the nth number
3=3^1.
9=3^2
27=3^3
81=3^4,
So the nth number is 3 ^ n