Tribonacci sequence

src/algorithms/math/tribonacci/tribonacci.js

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+/**
+ * Return a tribonacci sequence as an array.
+ *
+ * @param n
+ * @return {number[]}
+ */
+export default function tribonacci(n) {
+    const tribSequence = [0];
+    let currentValue = 1;
+  
+    if(n >= 2) {
+        tribSequence.push(currentValue);
+    }
+    
+    for (let i = 2; i < n; i++) {
+        tribSequence.push(currentValue);
+        currentValue += tribSequence[i - 1] + tribSequence[i - 2];       
+    }
+  
+    return tribSequence;
+}
+  

src/algorithms/math/tribonacci/tribonaciiNth.js

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+/**
+ * Calculate tribonacci number at specific position using Dynamic Programming approach.
+ *
+ * @param n
+ * @return {number}
+ */
+export default function tribonacciNth(n) {
+    const tribSequence = [0, 0, 1];
+    let currentValue = 1;
+    
+    for (let i = 3; i <= n; i++) {
+        tribSequence.push(currentValue);
+        currentValue += tribSequence[i - 1] + tribSequence[i - 2];       
+    }
+  
+    return tribSequence[n];
+}
+