This subject is calculus binomial series. So I'd like to know what is the sigma notation of this solution.

5 ) Given 1/ 5(1-27 Binomial Series , ( Itz )" = Ithat h ( n-1 ) 22 n (n-1) (n-2), at ..... 2! 3 ) ( * ) Nole ( 1+ ( - 2 ) ) - 1/ 2 (1- 20) By equation ( ) we have ( It (- 27 ) = 1+ (- 12) (-x )+ (- 1/2 ) ( 1/2 - ') (-20) 2 ! + ( 1/2 ) ( - 1/2 - 1 ) ( - 1/2 - 2 ) ( - 2 ) + .... 3 ! = 1+ - 2C + (- 1/ 2 ) ( - 3 / 2 ) 262 2 ! + ( - 1/2 ) ( - 3 / 2 ) ( - 5/ 2 ) ( - 2 ) 3 . . . . 31 = 1+1/2 - + 5 27 16 . The Binomial Series of is V(1 - DC ) ( It (-2 ) ) /2 8 16