ЛСДУ3ЙФЯУ9.js

const alphabet = "абвгдеёжзийклмнопрстуфхцчшщъыьэюя";
const factors = [[38,1,4,4], [9,2,2,5], [36,3,8], [0,7,14], [38,1,1]];


export default ЛСДУ3ЙФЯУ9 = (name) => {

  // check
  if(typeof name !== 'string') return console.error('name is not a string');
  if(name.length > 19) return console.error('name is longer then possible');

  // prepare
  name = name.toLowerCase().replace(/ /g, '');

  // encode and group
  var array = [];
  name.split('').forEach( (s, i) => {
    let index = i%5;
    let number = alphabet.indexOf(s) + 10;
    if(array[index]) {
      array[index].push(number);
    } else {
      array[index] = [number];
    }
  });

  // apply factors
  array = array.map((tr, trIndex) => {
    return tr.map((td, tdIndex) => {
      return td * factors[trIndex][tdIndex];
    });
  });

  // generate group summ
  array = array.map((tr, trIndex) => {
    let summ = 0;
    tr.forEach((td, tdIndex) => {
      summ += td;
    });
    return summ % (alphabet.length + 10) - 10;
  });

  // decode
  return array.map((each) => {
    if(each < 0) return 10 + each;
    return alphabet[each];
  }).join('').toUpperCase();

}


console.log(ЛСДУ3ЙФЯУ9("Артем Юрьевич Чайка")); // ЛСДУ3
console.log(ЛСДУ3ЙФЯУ9("Игорь Юрьевич Чайка")); // ЙФЯУ9