This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A360412 #21 Mar 06 2023 10:27:44 %S A360412 0,0,2,10,46,192,780,3090,12136,47100,181820,697856,2667642,10157814, %T A360412 38563342,146002012,551483230,2078722874,7821121318,29378487188 %N A360412 Number of binary words of length 2n with an even number of 1's which are not shuffle squares. %C A360412 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 A360412 Words with an odd number of 1's obviously are not shuffle squares. %F A360412 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 A360412 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 A360412 Cf. A191755. %K A360412 nonn,more %O A360412 0,3 %A A360412 _Bartlomiej Pawlik_, Feb 07 2023