Curve.sol function _helper

[tangkefu]

the desc
@return x^32/_MARKET_OPENING_SUPPLY^5

        for (uint256 index = 1; index <= _N; index++) {
            x = (x.mul(x)).div(_MARKET_OPENING_SUPPLY);
        }

with index = 1, x = x^2 / _MARKET_OPENING_SUPPLY
when run to next iteration, x = x^4/(_MARKET_OPENING_SUPPLY^2) / _MARKET_OPENING_SUPPLY

the doc is wrong

[wuyazero]

Yup, the real calculation is actually

@return x^32 / _MARKET_OPENING_SUPPLY^31

The number in the documentation is far off here...