https://github.com/bitcoin/bitcoin/blob/ff873a20a7f48698da3334acc570d97a07016ddf/src/validation.cpp#L1937-L1949

```cpp

CAmount GetBlockSubsidy(int nHeight, const Consensus::Params& consensusParams)

{

int halvings = nHeight / consensusParams.nSubsidyHalvingInterval;

// Force block reward to zero when right shift is undefined.

if (halvings >= 64)

return 0;

CAmount nSubsidy = 50 * COIN;

// Subsidy is cut in half every 210,000 blocks which will occur approximately every 4 years.

nSubsidy >>= halvings;

return nSubsidy;

}

```

No summation. No perfection. Most designs don't even have that "approximate" simple lke the one above has.

It's not a halving in computer science, it's a bit(coin) shift-right. PUT THAT ON A TSHIRT HUH.