I noticed a pattern a long time ago...

The direct numbers can be found by 11^{r}, and the sum can be found using 2^{r}. This means that the sum of the interior numbers on row 7 = 2^{7} - 2, or 126. As a matter of fact, the function is: \(\sum\triangle(r) = maximum([0, 2^{r}-2])\), where maximum (array) = the maximum value in the array.