Some ticket vendors refer to the front rows of section 131 (Rows F-J) as section 131A as these are the premium dugout box seats that are located in the first 5 rows behind the dugout. The remaining rows (K-OO) are located behind the dugout box seats and are the regular section 131 infield box seats.

View from Section 131 Row H at Great American Ballpark
The view above was taken from Row H in Section 131, which is referred to by some ticket brokers as Section 131A (the front portion of the section)