

A323443


Number of binary squares of length 2n that neither begin nor end with a shorter square.


2



2, 2, 2, 2, 2, 8, 14, 26, 42, 84, 154, 314, 610, 1220, 2400, 4836, 9590, 19220, 38326, 76684, 153110, 306294, 612082, 1224304, 2447620, 4895468, 9789002, 19578586, 39153160, 78307450, 156607388, 313216848, 659125988, 1491573926, 2990216920, 5536326412
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OFFSET

1,1


COMMENTS

A square is a word of the form XX, where X is a nonempty block.


LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..39
Rémy Sigrist, C program for A323443


EXAMPLE

For n = 7 the squares are (0100001)^2, (0100110)^2, (0110001)^2, (0110010)^2, (0111001)^2, (0111101)^2, (0111110)^2 and their complements.


PROG

(C) See Links section.


CROSSREFS

Similar to, but not the same as, A323442.
Sequence in context: A278241 A010671 A339164 * A334511 A291944 A253633
Adjacent sequences: A323440 A323441 A323442 * A323444 A323445 A323446


KEYWORD

nonn


AUTHOR

Jeffrey Shallit, Jan 15 2019


EXTENSIONS

More terms from Rémy Sigrist, Jan 19 2019


STATUS

approved



