collatz algorithm

collatz algorithm as function

snippets/collatz.md

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+### Collatz algorithm
+
+If n even then returns **n/2** otherwise (n is odd) **3n+1**.
+It uses the ternary operator.
+
+``` javascript
+    const collatz = n => (n % 2 == 0) ? (n/2) : (3*n+1); 
+    // collatz(8) --> 4
+    // collatz(5) --> 16
+
+```