Find the sum first 'n' terms of the series` (3+7+13+21+31+..)` ?

Find the sum to n terms of the series 5+ 11 + 19 + 29+ 41+ ……

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

Sum to n terms of the series 1+3+7+13+.. .=

Find the sum to n terms of the series , 5+11+19+29+41…

The sum to n terms of the series 11 + 103 + 1005 + …. Is

Find the sum upto n terms of the series 1+4+7+10+13+16+"...." .

Find the sum of first twenty terms of Arithmetic series 2 +7+12 + cdots using suitable formula.

Find the sum to n terms of the series . 3 xx 1^(2) + 5 xx 2^(2) + 7 xx 3^(2) + . . . . . .

(b)Find the sum of first n terns of the series 1^2+2^2+……+n^2 .