The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #9 Jun 07 2018 22:06:05
%S 2,3,4,4,4,8,10,14,12,20,34,33,52,61,76,96,126,200,258,442,568
%N Number of cyclic binary sequences of length n containing no abelian 4th powers.
%C Two length-n sequences are considered to be the same in the cyclic sense if one is a cyclic shift of the other.
%C An abelian 4th power is a word of the form x x' x'' x''', where x', x'', x''' are all permutations of x.
%e a(7) = 10, and the cyclic words are {0001001, 0001011, 0001101, 0010011, 0010101, 0010111, 0011011, 0011101, 0101011, 0110111}.
%K nonn,more
%O 1,1
%A _Jeffrey Shallit_, Jun 05 2018