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A200564 (2^(n^2)+2^((n^2+n)/2))/2. 0
1, 2, 12, 288, 33280, 16793600, 34360786944, 281475110928384, 9223372071214514176, 1208925819632221360750592, 633825300114132715146861084672, 1329227995784915909797295207699447808, 11150372599265311570918974863776009399828480 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The number of inequivalent n x n black and white checkerboards where two boards are indistinguishable if and only if they are identical after being reflected about the main diagonal.

Cycle index = (s_1^(n^2) + s_1^n*s_2^((n^2-n)/2))/2.

LINKS

Table of n, a(n) for n=0..12.

MATHEMATICA

Table[(2^(n^2)+2^((n^2+n)/2))/2, {n, 0, 10}]

CROSSREFS

Sequence in context: A211937 A176037 A057170 * A008338 A000178 A108395

Adjacent sequences:  A200561 A200562 A200563 * A200565 A200566 A200567

KEYWORD

nonn

AUTHOR

Geoffrey Critzer, Nov 19 2011

STATUS

approved

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Last modified February 25 12:43 EST 2018. Contains 299654 sequences. (Running on oeis4.)