Two mighty frogs jump once per unit time on the number line as described in the question.
The second frog starts at $x=0$ and jumps $i+1$ steps to the right just after $t=i$, so that at times $t=0,1,2,3,\ldots$ this frog is at positions $x=0,1,3,6,\ldots$ respectively. How many numbers of the form $7n+1$ (with $n$ an integer) does the frog visit from $t=0$ to $t=99$ (both endpoints included)? [3 points]