Sum of series: `1+2+3+.........+n` is

The sum to 100 terms of the series 1.2.3. + 2.3.4. + 3.4.5. + …+ n(n + 1) (n+2) + …. is integral multiple of

Find the sum of n terms of the series 1*2*3+2*3*4+3*4*5.........

Find the sum of the series 1 . 3^(2) + 2.5 ^(2) + 3.7^(2) +…+ to n terms

Find the sum to n terms of the series 1+(1+2)+(1+2+3)+......

The sum of the n terms of the series 1+(1+3)+(1+3+5)+... is

Find the sum of the series: 1.n+2.(n-1)+3.(n-2)+...+(n-1).2+n.1