Take the 15 smallest dominoes in a set (double blank through double four.)

In how many ways can they be arranged in a row such that the numbers on consecutive pieces match.

Count the two directions separately.

126,720 fifteen-domino rows where the consecutive pieces match. 

Edited on February 20, 2024, 7:03 am

Posted by K Sengupta on 2024-02-20 07:02:16