I need to learn F#, and need to get efficiency with working with immutable data and recursion.

Please, need help! I feel like I am still thinking in the object oriented mindset.

Write a program that asks the user for a number n and prints the sum of the numbers 1 to n. Don't use the math formula. Modify the previous program such that only multiples of three or five are considered in the sum, e.g. 3, 5, 6, 9, 10, 12, 15 for n=17 Write a function that returns the largest element in a list. Write function that reverses a list, without using and built-in List functions