get "libhdr"

manifest $( AMOUNT = 1200 $)

let gcd(a,b) =
    a>b -> gcd(a-b, b),
    a<b -> gcd(a, b-a),
    a

let mkstern(s, n) be
$(  s!1 := 1
    s!2 := 1
    for i=2 to n/2 do
    $(  s!(i*2-1) := s!i + s!(i-1)
        s!(i*2) := s!i
    $)
$)

let find(v, n, max) = valof
    for i=1 to max
        if v!i=n then resultis i

let findwrite(v, n, max) be
    writef("%I3 at %I4*N", n, find(v, n, max))

let start() be
$(  let stern = vec AMOUNT
    mkstern(stern, AMOUNT)

    writes("First 15 numbers: ")
    for i=1 to 15 do writef("%N ", stern!i)

    writes("*N*NFirst occurrence:*N")
    for i=1 to 10 do findwrite(stern, i, AMOUNT)
    findwrite(stern, 100, AMOUNT)

    if valof
    $(  for i=2 to AMOUNT
            unless gcd(stern!i, stern!(i-1)) = 1
                resultis false
        resultis true
    $) then
        writes("*NThe GCD of each pair of consecutive members is 1.*N")
$)