# August, 2009

Posts
• #### Project Euler Problem #1

Project Euler is pretty darn cool. It’s a bunch of mathematical problems that require programming to solve. I’m having fun doing them in F#. They start very simple but quickly become more difficult. Problem 1 is to find the sum of all the multiples...
• #### Project Euler Problem #2

Sum of even terms in Fibonacci sequence which are < four-million : (1, 1) |> Seq.unfold ( fun (a, b) -> Some(a, (b, a + b))) // fibs |> Seq.takeWhile ( fun x -> x <= 4000000) |> Seq.filter ( fun x -> x % 2 = 0) ...
• #### Project Euler Problem #3

Largest prime factor of 600851475143 : let primeFactors n = let isFactor n d = n % d = 0L let nextFactor n d = seq {d..n} |> Seq.find (isFactor n) (n, 2L, []) |> Seq.unfold ( fun (n, d, a) -> if isFactor n d then Some(d, ((n...
• #### Project Euler Problem #4

Largest palindrome from product of two 3-digit numbers : let isPalendrome n = let s = n.ToString() |> List.of_seq s = List.rev s seq { for a in 100..999 do for b in a..999 -> a * b } |> Seq.filter isPalendrome |> Seq.max