UPDATE: latest attempt here: https://github.com/olalonde/phemex-puzzle/blob/master/notebooks/solution.ipynb

phemex-puzzle.js

// First 21-digit prime number found in consecutive digits of e
// answer:
// 957496696762772407663
//
// in hexadecimal:
// 33E7EF9CABBAF6C56F

const bitcore = require("bitcore-lib");

const { PrivateKey, HDPrivateKey } = bitcore;

// console.log(new PrivateKey("deadbeef"));
const privKey = new PrivateKey("33E7EF9CABBAF6C56F");

console.log(privKey.toWIF());
console.log(new PrivateKey("33E7EF9CABBAF6C56F00000000000000").toWIF());

const hdPrivKey = HDPrivateKey.fromSeed(
  Buffer.from("33E7EF9CABBAF6C56F00000000000000", "hex")
);

console.log(hdPrivKey.privateKey.toWIF());

for (let i = 0; i < 30; i++) {
  for (let j = 0; j < 2; j++) {
    for (let k = 0; k < 50; k++) {
      // const child = hdPrivKey.deriveChild(`m/44'/0'/${i}'/${j}/${k}`);
      const child = hdPrivKey.deriveChild(`m/0/${i}/${k}`);
      console.log(child.privateKey.toWIF());
    }
  }
}

// node phemex-puzzle.js | pbcopy
// paste private keys in Electrum > Wallet > Private Keys > Import