Coprime triplets

Coprime triplets is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Task

Find and show the smallest number which is coprime to the last two predecessors and has not yet appeared; a(1)=1, a(2)=2.
p and q are coprimes if they have no common factors other than 1.
Let p, q < 50

Phix

function coprime_triplets(integer less_than=50)
    sequence cpt = {1,2}
    while true do
        integer m = 1
        while find(m,cpt) 
           or gcd(m,cpt[$])!=1
           or gcd(m,cpt[$-1])!=1 do
            m += 1
        end while
        if m>=less_than then exit end if
        cpt &= m
    end while
    return cpt
end function
sequence res = apply(true,sprintf,{{"%2d"},coprime_triplets()})
printf(1,"Found %d coprime triplets:\n%s\n",{length(res),join_by(res,1,10," ")})

Output:

Found 36 coprime triplets:
 1  2  3  5  4  7  9  8 11 13
 6 17 19 10 21 23 16 15 29 14
25 27 22 31 35 12 37 41 18 43
47 20 33 49 26 45

Ring

<lang ring> see "working..." + nl row = 2 numbers = 1:50 first = 1 second = 2 see "Coprime triplets are:" + nl see "" + first + " " + second + " "

    for n = 3 to len(numbers)
        flag1 = 1
        flag2 = 1
        if first < numbers[n]
           min = first
        else
           min = numbers[n]
        ok
        for m = 2 to min
            if first%m = 0 and numbers[n]%m = 0
               flag1 = 0
               exit
            ok
        next
        if second < numbers[n]
           min = second
        else
           min = numbers[n]
        ok
        for m = 2 to min
            if second%m = 0 and numbers[n]%m = 0 
               flag2 = 0
               exit
            ok
        next
        if flag1 = 1 and flag2 = 1
           see "" + numbers[n] + " "
           first = second 
           second = numbers[n] 
           del(numbers,n)
           row = row+1
           if row%10 = 0
              see nl
           ok
           n = 2
        ok
   next

   see nl + "Found " + row + " coprime triplets" + nl
   see "done..." + nl

</lang>

Output:

working...
Coprime triplets are:
1 2 3 5 4 7 9 8 11 13 
6 17 19 10 21 23 16 15 29 14 
25 27 22 31 35 12 37 41 18 43 
47 20 33 49 26 45 
Found 36 coprime triplets
done...

Wren

Translation of: Phix

Library: Wren-math

Library: Wren-seq

Library: Wren-fmt

<lang ecmascript>import "/math" for Int import "/seq" for Lst import "/fmt" for Fmt

var limit = 50 var cpt = [1, 2]

while (true) {

   var m = 1
   while (cpt.contains(m) || Int.gcd(m, cpt[-1]) != 1 || Int.gcd(m, cpt[-2]) != 1) {
       m = m + 1
   }
   if (m >= limit) break
   cpt.add(m)

} System.print("Coprime triplets under 50:") for (chunk in Lst.chunks(cpt, 10)) Fmt.print("$2d", chunk) System.print("\nFound %(cpt.count) such numbers.")</lang>

Output:

Coprime triplets under 50:
 1  2  3  5  4  7  9  8 11 13
 6 17 19 10 21 23 16 15 29 14
25 27 22 31 35 12 37 41 18 43
47 20 33 49 26 45

Found 36 such numbers.