procedure main()
    write("First 25 vampire numbers and their fangs:")
    every fangs := vampire(n := seq())\25 do write(right(n,20),":",fangs)
    write("\nOther numbers:")
    every n := 16758243290880 | 24959017348650 | 14593825548650 do
        write(right(n,20),": ",vampire(n)|"toothless")
end

procedure vampire(n)
    ns := string(n)
    if *ns % 2 = 1 then fail
    every (fangs := "") ||:= " "||fangCheck(n, *ns/2, f1 := 2 to integer(sqrt(n)), n/f1)
    if *fangs > 0 then return fangs
end

procedure fangCheck(n, n2, f1, f2)
    if f1*f2 ~= n then fail
    if n2 ~= *(f1|f2) then fail
    if (f1|f2) % 10 ~= 0 then
         if csort(f1||f2) == csort(n) then return "("||f1||","||f2||")"
end

procedure csort(s)  # Adapted from csort(s) in Icon IPL
    every (s1 := "", c := !cset(s)) do every find(c, s) do s1 ||:= c
    return s1
end