The sum of `n` terms of the series `1^2+2.2^2+3^2+2.4^2+5^2+2.6^2+....` is`(n(n+1)^2)/2` when n is even . when n is odd , the sum is

The sum of the first n terms of the series 1^2+2.2^2+3^2+2.4^2+5^2+2.6^2+........ is (n(n+1)^2)/2 when n is even. When n is odd the sum is

The sum of the first n terms of the series 1^2+ 2.2^2+3^2 +2.4^2+.... is (n(n+1)^2)/2 when n is even. Then the sum if n is odd , is

Sum to n terms the series : 1^2 - 2^2 + 3^2 - 4^2 + 5^2 - 6^2 + ...

The sum of n terms of the series 1^(2)-2^(2)+3^(2)-4^(2)+5^(2)-6^(2)+... is

The sum of first n terms of the series 1_(2) + 2.2^(2) + 3^(2) + 2.4^(2) + 5^(2) + 2.6^(2) + ...... is (n(n + 1)^(2))/4 when n is even. When n odd the sum is

The sum of first n terms of the series 1^(2)+ 2 . 2^(2) + 3^(2) + 2. 4 ^(2) + 5^(2) +… is n/2 (n+1) ^(2) when n is even , When n is odd then the sum will be-