2016 Update

Task/Digital-root-Multiplicative-digital-root/00DESCRIPTION

@@ -5,10 +5,12 @@ The [[wp:Multiplicative digital root|multiplicative digital root]] (MDR) and mul
 #* Increment <math>i</math>.
 # Return <math>i</math> (= MP) and <math>m</math> (= MDR)
 
+
 ;Task:
 * Tabulate the MP and MDR of the numbers 123321, 7739, 893, 899998
 * Tabulate MDR versus the first five numbers having that MDR, something like:
-<pre>MDR: [n0..n4]
+<pre>
+MDR: [n0..n4]
 ===  ========
   0: [0, 10, 20, 25, 30]
   1: [1, 11, 111, 1111, 11111]
@@ -19,9 +21,12 @@ The [[wp:Multiplicative digital root|multiplicative digital root]] (MDR) and mul
   6: [6, 16, 23, 28, 32]
   7: [7, 17, 71, 117, 171]
   8: [8, 18, 24, 29, 36]
-  9: [9, 19, 33, 91, 119]</pre>
+  9: [9, 19, 33, 91, 119]
+</pre>
 Show all output on this page.
 
+
 ;References:
 * [http://mathworld.wolfram.com/MultiplicativeDigitalRoot.html Multiplicative Digital Root] on Wolfram Mathworld.
 * [http://oeis.org/A031347 Multiplicative digital root] on The On-Line Encyclopedia of Integer Sequences.
+<br><br>

Task/Digital-root-Multiplicative-digital-root/Elixir/digital-root-multiplicative-digital-root.elixir

@@ -26,12 +26,12 @@ defmodule Digital do
 
   defp add_map(n, m, map) do
     {mdr, _persist} = mdroot(n)
-    new_map = Dict.update(map, mdr, [n], fn vals -> [n | vals] end)
-    min_len = Dict.values(new_map) |> Enum.map(&length(&1)) |> Enum.min
+    new_map = Map.update(map, mdr, [n], fn vals -> [n | vals] end)
+    min_len = Map.values(new_map) |> Enum.map(&length(&1)) |> Enum.min
     if min_len < m, do: add_map(n+1, m, new_map),
                   else: new_map
   end
 end
 
 Digital.task1([123321, 7739, 893, 899998])
-Digital.task2(5)
+Digital.task2

Task/Digital-root-Multiplicative-digital-root/PARI-GP/digital-root-multiplicative-digital-root.pari

@@ -0,0 +1,3 @@
+a(n)=my(i);while(n>9,n=factorback(digits(n));i++);[i,n];
+apply(a, [123321, 7739, 893, 899998])
+v=vector(10,i,[]); forstep(n=0,oo,1, t=a(n)[2]+1; if(#v[t]<5,v[t]=concat(v[t],n); if(vecmin(apply(length,v))>4, return(v))))

Task/Digital-root-Multiplicative-digital-root/Perl-6/digital-root-multiplicative-digital-root.pl6

@@ -1,6 +1,6 @@
 sub multiplicative-digital-root(Int $n) {
     return .elems - 1, .[.end]
-        given $n, {[*] .comb} ... *.chars == 1
+        given cache($n, {[*] .comb} ... *.chars == 1)
 }
 
 for 123321, 7739, 893, 899998 {