A127503 - cp's OEIS frontend

A127503 Number of n X n matrices A with 1's on the main diagonal and -1's and 0's elsewhere such that A + A' has only 0's and -1's off the main diagonal and is positive semi-definite.

%I A127503 #4 Mar 30 2012 17:26:59
%S A127503 1,3,27,281,3945,70635,1437555,30357425,628337745
%N A127503 Number of n X n matrices A with 1's on the main diagonal and -1's and 0's elsewhere such that A + A' has only 0's and -1's off the main diagonal and is positive semi-definite.
%C A127503 For number of different values of A + A' see A084553.
%Y A127503 Cf. A085657, A085658, A080858, A083029, A038379, A127502.
%K A127503 nonn,more,nice
%O A127503 1,2
%A A127503 _Max Alekseyev_, Jan 16 2007

cp's OEIS Frontend

A127503 Number of n X n matrices A with 1's on the main diagonal and -1's and 0's elsewhere such that A + A' has only 0's and -1's off the main diagonal and is positive semi-definite.