Inverse Digit Sum II (noch nicht übersetzt)
Problem 685
Writing down the numbers which have a digit sum of 10 in ascending order, we get: 19,28,37,46,55,64,73,82,91,109,118,…
Let f(n,m) be the mth occurrence of the digit sum n. For example, f(10,1)=19, f(10,10)=109 and f(10,100)=1423.
Let S(k)=k∑n=1f(n3,n4). For example S(3)=7128 and S(10)≡32287064mod1000000007.
Find S(10000) modulo 1000000007.