Number of squarefree words of length 6 in an (n+1)-ary alphabet.

Terms

a(0) =0a(1) =42a(2) =696a(3) =4260a(4) =16680a(5) =50190a(6) =126672a(7) =281736a(8) =569520a(9) =1068210a(10) =1886280a(11) =3169452a(12) =5108376a(13) =7947030a(14) =11991840a(15) =17621520a(16) =25297632a(17) =35575866a(18) =49118040a(19) =66704820a(20) =89249160a(21) =117810462a(22) =153609456a(23) =198043800a(24) =252704400a(25) =319392450a(26) =400137192