Number of squarefree words of length n in a 5-ary alphabet.

Terms

a(0) =5a(1) =20a(2) =80a(3) =300a(4) =1140a(5) =4260a(6) =15960a(7) =59580a(8) =222600a(9) =830880a(10) =3102120a(11) =11578800a(12) =43220940a(13) =161324400a(14) =602159940a(15) =2247585300a(16) =8389237320a(17) =31313155560a(18) =116877700500a(19) =436250537520