2016 Update

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]