Programming Exercise (HP-15C, 15C LE - and others)

[Tugdual]

Nobody mentioned that entering $$\sum _{ K=1 }^{ 10000 }{ \frac { { (-1 })^{ K+1 } }{ K } }$$ on the Prime with no need for any sort of coding would instantly return 0.693097183025
Is that off scope consideration for this thread?
I know that the prime is blazing fast but the speed is so impressive that I wonder if the calculator is actually performing a loop?