Scala implementation of the legos problem, infinitely recursing!!!

Legos.scala

import scala.collection.mutable._

object Legos {

  val mod = 1000000007;

  def t(width:Int):Int = {
    if(width < 0) 0
    if(width == 0) 1
    t(width-1) + t(width-2) + t(width-3) + t(width-4)
  }

  def allNonSolid(width:Int,height:Int):Int = {
    Math.pow(t(width).toFloat,height.toFloat).toInt
  }

  def overX(x:Int,height:Int,width:Int):Int = {
    println(x)
    permuteSolids(x,height) * allNonSolid(width-x,height)
  }

  def permuteSolids(height:Int,width:Int):Int = {
    allNonSolid(width,height) - (1 to width).map( overX(_,height,width) ).sum
  }

  def printmod(a:Int){
    println(a % mod)
  }

  def main(args: Array[String]) {
     io.Source.stdin.getLines
      .map(_.trim.split("\\s+").map(_.toInt))    // split and convert to ints
      .collect { case Array(a, b) => permuteSolids(a, b) }   // pass to f if there are two arguments
      .foreach(printmod)  
  }
}