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Number of singular n X n (-1,0,1)-matrices.
4

%I #23 May 27 2024 06:50:42

%S 0,1,33,7875,15099201,237634987683,30805715676309201

%N Number of singular n X n (-1,0,1)-matrices.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SingularMatrix.html">Singular Matrix.</a>

%H Minfeng Wang, <a href="/A057981/a057981.cpp.txt">C++ program to calculate A057981</a>

%F a(n) = A060722(n) - A056989(n). - _Alois P. Heinz_, Dec 02 2019

%Y Complement of A056989.

%Y Cf. A060722, A330134.

%K nonn,more

%O 0,3

%A _Eric W. Weisstein_, Oct 23 2000

%E a(5) from _Giovanni Resta_, Feb 20 2009

%E a(0)=0 prepended by _Alois P. Heinz_, Dec 02 2019

%E a(0)-a(5) confirmed and a(6) added by _Minfeng Wang_, May 01 2024