Question 45
(YUG) An alphabet consists of $n$ letters. What is the maximal length of a word, if
(i) two neighboring letters in a word are always different, and
(ii) no word $abab$ $(a\ne b)$ can be obtained by omitting letters from the given word?
(i) two neighboring letters in a word are always different, and
(ii) no word $abab$ $(a\ne b)$ can be obtained by omitting letters from the given word?