2016 Update

Task/Hailstone-sequence/REBOL/hailstone-sequence.rebol

@@ -0,0 +1,31 @@
+hail: func [
+	"Returns the hailstone sequence for n"
+	n [integer!]
+	/local seq
+] [
+	seq: copy reduce [n]
+	while [n <> 1] [
+		append seq n: either n % 2 == 0 [n / 2] [3 * n + 1]
+	]
+	seq
+]
+
+hs27: hail 27
+print [
+	"the hail sequence of 27 has length" length? hs27
+	"and has the form " copy/part hs27 3 "..."
+	back back back tail hs27
+]
+
+maxN: maxLen: 0
+repeat n 99999 [
+	if (len: length? hail n) > maxLen [
+		maxN: n
+		maxLen: len
+	]
+]
+
+print [
+	"the number less than 100000 with the longest hail sequence is"
+	maxN "with length" maxLen
+]