Generate a random number, but every random seconds in LUA/Love2d

I am trying to generate a random number, every random seconds (the final purpose would be to change the color of a block from time to time, randomly).

For that, I am using the Hump library (http://vrld.github.io/hump/#hump.timer).

Here is my code at the moment, I am true beginner in LUA/Love2d coding. It generates a number, and displays it every seconds, instead of every random seconds... (but the random seconds is also generated). I don't really understand why it is not working.

local Timer = require "timer"

function love.load()
    text="t"
    number2=1
end

local f = function()
math.randomseed(os.time())
    number = math.random( 2,10 )
    text="in " .. number2 .. " seconds (random)...  random number =" .. number
    return true
end

function love.update(dt)

    number2 = math.random( 2,4 ) 
    Timer.update(number2)
    Timer.addPeriodic(number2, f)
end

function love.draw()
    love.graphics.print( text, 330, 300 )
end

Thanks for any help !

While I am not familiar with Hump, it seems that you can easily use the timer's add function for your purpose, as it will call the function exactly once after x seconds, allowing you to schedule the next execution with a different delay:

local timer = require("timer")
local text = ""

local function tick()
  -- Generate random number
  local newNumber = math.random(2, 10)
  local newDelay  = math.random(2,  4)
  text = ("Current number: %d, next in %d seconds!"):format(newNumber, newDelay)

  -- Actually schedule the next call
  timer.add(newDelay, tick)
end


function love.load()
  tick()
end

function love.update(dt)
  timer.update(dt)
end

function love.draw()
  love.graphics.print(text, 330, 300)
end