JS solution for the challenege on https://trello.com/jobs/developer

trello-solve.js

// for some reason the challenege only let you use these letters, not full A-Z
var letters = "acdegilmnoprstuw";

// Implementation of their hash function to test against
function doHash(string) {
  var hash = 7;
  for(var i = 0; i < string.length; i++) {
    hash = (hash * 37 + letters.indexOf(string[i]));
  }
  return hash;
}

// Code to work back, one letter at a time, until a valid string is found for the hash
function testChar(currentLetter, hash, partialMatch) {
  var x = (hash - letters.indexOf(currentLetter)) / 37;
  if (Math.floor(x) - x == 0.0) {
    if (x == 7) { // Their hash starts with 7 so if we found this int, we're done
      console.log('Match Found: ' + currentLetter + partialMatch);
      return true;
    }

    // If the currentLetter was valid then recurse down with other letter guesses
    for (var i = 0; i < letters.length; i++) {
      testChar(letters[i], x, currentLetter + partialMatch);
    }
  }
  else {
    // If we didn't get an int after working back then the currentLetter wasn't valid
    return false;
  }
}

// Break a hash
function breakHash(hash) {
  for (var i = 0; i < letters.length; i++) {
    testChar(letters[i], hash, '');
  }
}