#2**0 **

The sum of rows 0 through n is = -1 + 2^(n + 1)=-1 + 2^(15+1) =65,535 ?? Just guessing !!

Guest Oct 24, 2017

#3**+2 **

The 121st element will be the first number in the 16th row = 1 ... [ I am letting the "1" at the top of the triangle be the first row ]

The sum of the entries in any row will be 2^(r - 1) where r is the row number

So....the sum of the first 121 elements will be

16

Σ 2^(r - 1) + 1 = [ 65535 + 1 ] = 65536

1

CPhill Oct 24, 2017