A195889 - OEIS

%I #5 Dec 18 2015 18:17:46

%S 1,1,11,671,241221,584257875

%N Number of lower triangles of an n X n integer array with all row and column sums zero and all row and column sums of squares <=50

%C Column 5 of A195892

%e Some solutions for n=4

%e ..0........0........0........0........0........0........0........0

%e .-5.5.....-4.4......5-5.....-1.1.....-1.1.....-2.2.....-4.4......3-3

%e ..5-1-4...-1.1.0....0.4-4....5-1-4....5-1-4....2-5.3....0-1.1....1-2.1

%e ..0-4.4.0..5-5.0.0.-5.1.4.0.-4.0.4.0.-4.0.4.0..0.3-3.0..4-3-1.0.-4.5-1.0

%K nonn

%O 1,3

%A _R. H. Hardin_ Sep 24 2011