1 files changed, 101 insertions, 0 deletions
diff --git a/challenge-168/roger-bell-west/lua/ch-2.lua b/challenge-168/roger-bell-west/lua/ch-2.lua
new file mode 100755
index 0000000000..978f8ed462
--- /dev/null
+++ b/challenge-168/roger-bell-west/lua/ch-2.lua
@@ -0,0 +1,101 @@
+#! /usr/bin/lua
+
+function genprimes(mx)
+   local primesh = {}
+   for i = 2, 3 do
+      primesh[i] = true
+   end
+   for i = 6, mx, 6 do
+      for j = i-1, i+1, 2 do
+         if j <= mx then
+            primesh[j]=true
+         end
+      end
+   end
+   local q={2,3,5,7}
+   local p=table.remove(q,1)
+   local mr=math.floor(math.sqrt(mx))
+   while p <= mr do
+      if primesh[p] ~= nil then
+         for i = p*p,mx,p do
+            primesh[i] = nil
+         end
+      end
+      if #q < 2 then
+         table.insert(q,q[#q]+4)
+         table.insert(q,q[#q]+2)
+      end
+      p=table.remove(q,1)
+   end
+   local primes = {}
+   for k,v in pairs(primesh) do
+      table.insert(primes,k)
+   end
+   table.sort(primes)
+   return primes
+end
+
+function primefactor(n)
+   local f={}
+   local m=n
+   for k,p in pairs(genprimes(1+math.floor(math.sqrt(m)))) do
+      while m % p == 0 do
+         m=math.floor(m/p)
+         if f[p] == nil then
+            f[p]=1
+         else
+            f[p] = f[p] + 1
+         end
+         if m==1 then
+            break
+         end
+      end
+   end
+   if m>1 then
+      if f[m] == nil then
+         f[m]=1
+      else
+         f[m] = f[m] + 1
+      end
+   end
+   return f
+end
+
+function homeprime(n0)
+   local n = n0
+   while true do
+      local pfc = 0
+      local ns = ""
+      local t = primefactor(n)
+      local kl = {}
+      for k,v in pairs(t) do
+         pfc = pfc + v
+         table.insert(kl,k)
+      end
+      table.sort(kl)
+      if pfc == 1 then
+         break
+      end
+      for k,v in pairs(kl) do
+         for i = 1,t[v] do
+            ns = ns .. v
+         end
+      end
+      n = 0 + ns
+   end
+   return n
+end
+
+if homeprime(10) == 773 then
+   io.write("Pass")
+else
+   io.write("FAIL")
+end
+io.write(" ")
+
+if homeprime(16) == 31636373 then
+   io.write("Pass")
+else
+   io.write("FAIL")
+end
+print("")