
Sum of Digits - Experience #23
For a positive integer $k$, define $d(k)$ as the sum of the digits of $k$ in its usual decimal representation. Thus $d(42) = 4+2 = 6$.
For a positive integer $n$, define $S(n)$ as the number of positive integers $k \lt 10^n$ with the following properties :
- $k$ is divisible by $23$ and
- $d(k) = 23$.
Find $S(11^{12})$ and give your answer mod $10^9$.