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A086829
Number of n X n matrices on n^2 distinct symbols modulo rotations and reflections.
2
1, 3, 45360, 2615348736000, 1938901255416373248000000, 46499165848737652183499931018854400000000, 76035233004283445109031520415161922110944103922401280000000000
OFFSET
1,2
COMMENTS
Also the number of distinct adjacency matrices on the n X n grid graph P_n x P_n. - Eric W. Weisstein, May 01 2017
LINKS
Eric Weisstein's World of Mathematics, Adjacency Matrix
Eric Weisstein's World of Mathematics, Grid Graph
Eric Weisstein's World of Mathematics, Square Matrix
FORMULA
a(n) = (n^2)!/8, n>1. - Vladeta Jovovic, Aug 10 2003
MATHEMATICA
Table[Piecewise[{{1, n == 1}}, (n^2)!/8], {n, 7}]
CROSSREFS
Cf. A087074.
Sequence in context: A140656 A135760 A003541 * A190722 A171365 A115976
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Aug 08 2003
EXTENSIONS
More terms from Sam Alexander, Feb 27 2004
STATUS
approved