221799domain: NAppears in sequencesNumber of ways to tile a 5 X n area with 1 X 1 and 2 X 2 tiles.at n=10A054855Number of ways to tile a 10 X n rectangle with 1 X 1 and 2 X 2 tiles.at n=5A063654Numbers k such that gcd(2^k + 1, k! - 1) has a prime divisor different from 2*k + 1.at n=0A366824