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%I #21 Mar 06 2023 10:27:44
%S 0,0,2,10,46,192,780,3090,12136,47100,181820,697856,2667642,10157814,
%T 38563342,146002012,551483230,2078722874,7821121318,29378487188
%N Number of binary words of length 2n with an even number of 1's which are not shuffle squares.
%C A shuffle square is a word obtained by self-shuffling, e.g., the French word "tuteurer" is a shuffle square as it can be obtained by self-shuffling the word "tuer".
%C Words with an odd number of 1's obviously are not shuffle squares.
%F a(n) = 2^(2n-1) - A191755(n), since the number of binary words of length 2n with an even number of 1's is 2^(2n-1).
%e a(3)=10, since the binary words of length 6 with an even number of 1's which are not shuffle squares are 000110, 010001, 011000, 011101, 011110, 100001, 100010, 100111, 101110 and 111001.
%Y Cf. A191755.
%K nonn,more
%O 0,3
%A _Bartlomiej Pawlik_, Feb 07 2023
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