Catalan number upload

Catalan.java

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+import java.util.Scanner;
+
+class Catalan {
+
+	// find nth Catalan number
+    public static int catalanDP(int n)
+	{
+
+		int cat[] = new int[n + 2];
+
+		// Initialize first two values in table
+		cat[0] = 1;
+		cat[1] = 1;
+
+		for (int i = 2; i <= n; i++) {
+			cat[i] = 0;
+			for (int j = 0; j < i; j++) {
+				cat[i] += cat[j] * cat[i - j - 1];
+			}
+		}
+
+		// Return last entry
+		return cat[n];
+	}
+
+	// Driver code
+	public static void main(String[] args)
+	{
+
+        // Catalan numbers are a sequence of positive integers, where the nth term in the sequence, denoted Cn, 
+        // is found in the following formula: (2n)! / ((n + 1)!n!)
+
+        Scanner in = new Scanner(System.in);
+        System.out.println("Enter n (upto 20th catalan numbers will be printed): ");
+        int n = in.nextInt();
+        while(n>=20 || n<=0){
+            System.out.print("Enter n < 20: ");
+            n = in.nextInt();
+        }
+        in.close();
+		for (int i = 0; i < n; i++) {
+			System.out.print(catalanDP(i) + " ");
+		}
+	}
+}