%I #21 Jan 08 2019 19:11:42
%S 1,2,2,4,6,8,16,24,46,84,160,300,588,1136,2236,4388,8690
%N Number of (strongly) superprimitive binary sequences of length n.
%C A string x of length n is (weakly) quasiperiodic if there is a string w of length < n for which copies can be placed (possibly overlapping; possibly hanging off the left and right ends of x) that completely cover x. For example, x = 001101 is weakly quasiperiodic with quasiperiod w = 0110; three copies of w suffice to cover x. A string is (strongly) superprimitive if it is not weakly quasiperiodic.
%H A. Apostolico, M. Farach, and C. S. Iliopoulos, <a href="https://doi.org/10.1016/00200190(91)90056N">Optimal superprimitivity testing for strings</a>, Info. Proc. Letters 39 (1991), 1720.
%e a(6) = 16 because the 8 strings
%e 000001,
%e 000011,
%e 000101,
%e 000111,
%e 001011,
%e 001111,
%e 010111,
%e 011111
%e and their complements are strongly superprimitive.
%K nonn,more
%O 0,2
%A _Jeffrey Shallit_, Mar 13 2013
