Is it possible to derive a formula from a sequence of numbers?

Question

Mathematics

There is a sequence of numbers:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 ...
Is it possible to determine the numbers in bold using the formula?

Answer 1

if we are talking about matching the following two rows:
1 -> 7
2 -> 8
3 -> 9
4 -> 12
5 -> 13
6 -> 14
7 -> 17
8 -> 18
9 -> 19...
then I would suggest this formula:
(where div is the integer division operator)