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%I #19 Dec 17 2016 10:30:23
%S 0,1,27,1296,100000,11390625,1801088541,377801998336,101559956668416,
%T 34050628916015625,13931233916552734375,6831675453247426400256,
%U 3955759092264800909058048,2670419511272061205254504361
%N Number of n X n matrices with exactly 2 1's in each row, other entries 0.
%F a(n) = binomial(n,2)^n.
%t Table[ Binomial[n, 2]^n, {n, 1, 16} ]
%o (PARI) a(n) = binomial(n,2)^n \\ _Charles R Greathouse IV_, Dec 16 2016
%Y Cf. A001499.
%K nonn
%O 1,3
%A Sharon Sela (sharonsela(AT)hotmail.com), Jan 01 2002
%E More terms from _Robert G. Wilson v_, Jan 03 2002