import java.io.*;
import java.util.*;
public class Main {

	static class PairComparator implements Comparator<Pair> {
		@Override
		public int compare(Pair x, Pair y) {
			if (x.val < y.val)return -1;
			if (x.val > y.val)return 1;
			if (x.val == y.val){
				if (x.ind < y.ind)return -1;
				if (x.ind > y.ind)return 1;
			}
			return 0;
		}
	}

    static class Pair{
        int ind, val;
        Pair(int i, int v){
            ind=i;
            val=v;
        }
    }

   static void func() throws Exception {
	   int n,m;
	   n = sc.nextInt();
	   m = sc.nextInt();
	   if (m==0){pw.println(0);
		   return;
	   }

	   int times= n/(m + 1);
	   long res = (times+1)* (m)*(2*(n-times)-(m-1)*(times+1))/2;
	   if (n>1 && n%2==1 && (n/2)+1 == m)res++;
	   pw.println(res);

		

   }


    static PrintWriter pw;
    static MScanner sc;

    public static void main(String[] args) throws Exception {

        pw = new PrintWriter(System.out);
        sc = new MScanner(System.in);

        int tests = 1;
       tests =sc.nextInt(); //comment this line
        while (tests-- > 0){
            func();
            pw.flush();
        }

    }

    static class MScanner {
        StringTokenizer st;
        BufferedReader br;

        public MScanner(InputStream system) {
            br = new BufferedReader(new InputStreamReader(system));
        }

        public MScanner(String file) throws Exception {
            br = new BufferedReader(new FileReader(file));
        }

        public String next() throws IOException {
            while (st == null || !st.hasMoreTokens())
                st = new StringTokenizer(br.readLine());
            return st.nextToken();
        }

        public int[] intArr(int n) throws IOException {
            int[] in = new int[n];
            for (int i = 0; i < n; i++)
                in[i] = nextInt();
            return in;
        }

        public long[] longArr(int n) throws IOException {
            long[] in = new long[n];
            for (int i = 0; i < n; i++)
                in[i] = nextLong();
            return in;
        }

        public int[] intSortedArr(int n) throws IOException {
            int[] in = new int[n];
            for (int i = 0; i < n; i++)
                in[i] = nextInt();
            shuffle(in);
            Arrays.sort(in);
            return in;
        }

        public long[] longSortedArr(int n) throws IOException {
            long[] in = new long[n];
            for (int i = 0; i < n; i++)
                in[i] = nextLong();
            shuffle(in);
            Arrays.sort(in);
            return in;
        }

        public Integer[] IntegerArr(int n) throws IOException {
            Integer[] in = new Integer[n];
            for (int i = 0; i < n; i++)
                in[i] = nextInt();
            return in;
        }

        public Long[] LongArr(int n) throws IOException {
            Long[] in = new Long[n];
            for (int i = 0; i < n; i++)
                in[i] = nextLong();
            return in;
        }

        public String nextLine() throws IOException {
            return br.readLine();
        }

        public int nextInt() throws IOException {
            return Integer.parseInt(next());
        }

        public double nextDouble() throws IOException {
            return Double.parseDouble(next());
        }

        public char nextChar() throws IOException {
            return next().charAt(0);
        }

        public long nextLong() throws IOException {
            return Long.parseLong(next());
        }

        public boolean ready() throws IOException {
            return br.ready();
        }

        public void waitForInput() throws InterruptedException {
            Thread.sleep(3000);
        }
    }

    static void shuffle(int[] in) {
        for (int i = 0; i < in.length; i++) {
            int idx = (int) (Math.random() * (i+1));
            int tmp = in[i];
            in[i] = in[idx];
            in[idx] = tmp;
        }
    }

    static void shuffle(long[] in) {
        for (int i = 0; i < in.length; i++) {
            int idx = (int) (Math.random() * (i+1));
            long tmp = in[i];
            in[i] = in[idx];
            in[idx] = tmp;
        }
    }
}
