get "libhdr"

let sumdigitsq(n) =
    n=0 -> 0, (n rem 10)*(n rem 10)+sumdigitsq(n/10)

let happy(n) = valof
$(  let seen = vec 255
    for i = 0 to 255 do i!seen := false
    $(  n!seen := true
        n := sumdigitsq(n)
    $) repeatuntil n!seen
    resultis 1!seen
$)

let start() be
$(  let n, i = 0, 0
    while n < 8 do
    $(  if happy(i) do
        $(  n := n + 1
            writef("%N ",i)
        $)
        i := i + 1
    $)
    wrch('*N')
$)