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

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