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A127234 a(n) = n! (sum(1..n-1))!. 2
1, 2, 36, 17280, 435456000, 941525544960000, 257498348545415577600000, 12293098054744302855420641280000000, 134988938425519353794787639744975077376000000000, 434085115076654530026451920435442716425635693068288000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Number of distinct n x n symmetrical matrices containing A000217(n+1) different elements which have that same trace.
LINKS
MATHEMATICA
Table[n! (Sum[x, {x, 1, n-1}])!, {n, 1, 10}]
Table[n!((n(n-1))/2)!, {n, 10}] (* Harvey P. Dale, May 08 2013 *)
CROSSREFS
Sequence in context: A308942 A134366 A265944 * A326961 A181555 A306644
KEYWORD
nonn
AUTHOR
Artur Jasinski, Jan 09 2007, Jan 11 2007
EXTENSIONS
Edited by Jason G. Wurtzel, Oct 08 2010
Corrected and extended by Harvey P. Dale, May 08 2013
STATUS
approved

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Last modified April 20 21:11 EDT 2024. Contains 371845 sequences. (Running on oeis4.)