function binarySearchR(array, valor, lb, ub)
    if ub < lb then
        return false
    else
        mitad = floor((lb + ub) / 2)
        if valor < array[mitad] then return binarySearchR(array, valor, lb, mitad-1)
        if valor > array[mitad] then return binarySearchR(array, valor, mitad+1, ub)
        if valor = array[mitad] then return mitad
    end if
end function