Number of words of length 3n formed with 3 types of letter where the number of each type == 0 (mod 3).
A391468
Number of words of length 3n formed with 3 types of letter where the number of each type == 0 (mod 3).
Terms
- a(0) =1a(1) =3a(2) =63a(3) =2187a(4) =59535a(5) =1594323a(6) =43033599a(7) =1162261467a(8) =31381413903a(9) =847288609443
External references
- oeis: A391468