module _43
open System
open common
let pandigitalDivisible =
    let comb (i : string) (j : string) =
        match i, j with
        | i,j when i.[1] = j.[0] && i.[2] = j.[1] -> Some(String.Concat((string i.[0]), j))
        | _ -> None

    let prMul =
        [17;13;11;7;5;3;2]
        |> List.map 
            (
                multiples
                >> Seq.map string
                >> Seq.skipWhile (String.length >> (>) 3)
                >> Seq.takeWhile (String.length >> (>) 4)
            )

    
    
//    let lnth i l = List.nth l i
//    let lnthDivs i n l = lnth i l >> (%) n >> (=) 0
//    [0..9] |> Set.ofSeq |> permutations 
//    |> Seq.filter (lnth 0 >> (<>) 0)
//    |> Seq.filter (lnth 3 >> (%) 2 >> (=) 0)
//    //|> Seq.filter (lnth 5 >> (%) 5 >> (=) 0)
//    |> Seq.length