2016 Update

Task/Hailstone-sequence/Mathematica/hailstone-sequence-1.math

@@ -1 +1 @@
-HailstoneFP[n_Integer] := Most[FixedPointList[Which[# == 1, 1, EvenQ[#] , #/2, OddQ[#], (3*# + 1)] &, n]]
+HailstoneF[n_] := NestWhileList[If[OddQ@#, 3 # + 1, #/2] &, n, # > 1 &]

Task/Hailstone-sequence/Mathematica/hailstone-sequence-2.math

@@ -1,3 +1 @@
-HailstoneR[1] := {1}
-HailstoneR[n_Integer] := Prepend[HailstoneR[3 n + 1], n] /; OddQ[n] && n > 0
-HailstoneR[n_Integer] := Prepend[HailstoneR[n/2], n] /; EvenQ[n] && n > 0
+HailstoneFP[n_] := Most@FixedPointList[Switch[#, 1, 1, _?OddQ , 3# + 1, _, #/2] &, n]

Task/Hailstone-sequence/Mathematica/hailstone-sequence-3.math

@@ -1,4 +1,3 @@
-hailstone[n_Integer] := Block[{sequence = {}, c = n},
-                                    While[c > 1, c = If[EvenQ[c], c/2, 3 c + 1];
-                                                 AppendTo[sequence, c]];
-                              sequence]
+HailstoneR[1] = {1}
+HailstoneR[n_?OddQ] := Prepend[HailstoneR[3 n + 1], n]
+HailstoneR[n_] := Prepend[HailstoneR[n/2], n]

Task/Hailstone-sequence/Mathematica/hailstone-sequence-4.math

@@ -1,12 +1,2 @@
-Hailstone[n_] :=
- NestWhileList[Which[Mod[#, 2] == 0, #/2, True, ( 3*# + 1) ] &, n, # != 1 &];
-c27 = Hailstone@27;
-Print["Hailstone sequence for n = 27: [", c27[[;; 4]], "...", c27[[-4 ;;]], "]"]
-Print["Length Hailstone[27] = ", Length@c27]
-
-longest = -1; comp = 0;
-Do[temp = Length@Hailstone@i;
- If[comp < temp, comp = temp; longest = i],
- {i, 100000}
- ]
-Print["Longest Hailstone sequence at n = ", longest, "\nwith length = ", comp];
+HailstoneP[n_] := Module[{x = {n}, s = n},
+ While[s > 1, x = {x, s = If[OddQ@s, 3 s + 1, s/2]}]; Flatten@x]

Task/Hailstone-sequence/Mathematica/hailstone-sequence-5.math

@@ -1 +1,14 @@
-With[{seq = HailstoneFP[27]}, { Length[seq], Take[seq, 4], Take[seq, -4]}]
+Hailstone[n_] :=
+ NestWhileList[Which[Mod[#, 2] == 0, #/2, True, ( 3*# + 1) ] &, n, # != 1 &];
+
+
+c27 = Hailstone@27;
+Print["Hailstone sequence for n = 27: [", c27[[;; 4]], "...", c27[[-4 ;;]], "]"]
+Print["Length Hailstone[27] = ", Length@c27]
+
+longest = -1; comp = 0;
+Do[temp = Length@Hailstone@i;
+ If[comp < temp, comp = temp; longest = i],
+ {i, 100000}
+ ]
+Print["Longest Hailstone sequence at n = ", longest, "\nwith length = ", comp];

Task/Hailstone-sequence/Mathematica/hailstone-sequence-6.math

@@ -1 +1 @@
-Short[HailstoneFP[27],0.45]
+With[{seq = HailstoneFP[27]}, { Length[seq], Take[seq, 4], Take[seq, -4]}]

Task/Hailstone-sequence/Mathematica/hailstone-sequence-7.math

@@ -1 +1 @@
-MaximalBy[Table[{i, Length[HailstoneFP[i]]}, {i, 100000}], Last]
+Short[HailstoneFP[27],0.45]

Task/Hailstone-sequence/Mathematica/hailstone-sequence-8.math

@@ -0,0 +1 @@
+MaximalBy[Table[{i, Length[HailstoneFP[i]]}, {i, 100000}], Last]