Let \( A_1, A_2, A_3 \) be the three A.P. with the same common difference \( d \) and having their first terms as \( A, A+1, A+2 \) respectively. Let \( a, b, c \) be the \( 7^{\text{th}}, 9^{\text{th}}, 17^{\text{th}} \) terms of \( A_1, A_2, A_3 \), respectively such that
. If \( a = 29 \), then the sum of first \( 20 \) terms of an AP whose first term is \( c-a-b \) and common difference is \( \frac{d}{12} \), is equal to ________.
