%I #9 Apr 07 2020 15:03:15

%S 1,232,22054,902962,20758650,313568636,3444274966,29445929253,

%T 205617134345,1214911142900,6238854236951,28428076580526,

%U 116844463511314,438968651731176,1523790358321400,4931487866349689,14991891923697588,43084786003434739,117690415289036999

%N Number of (7*n) X 7 binary arrays with rows in nonincreasing order, n ones in every column and no more than 2 ones in any row.

%C Number of 7 X 7 symmetric matrices with nonnegative integer entries and all row and column sums n. - _Andrew Howroyd_, Apr 07 2020

%H Andrew Howroyd, <a href="/A188401/b188401.txt">Table of n, a(n) for n = 0..30</a>

%e Some solutions for 14X7

%e ..1..1..0..0..0..0..0....1..1..0..0..0..0..0....1..1..0..0..0..0..0

%e ..1..0..0..0..0..0..0....1..0..0..0..0..0..1....1..0..0..1..0..0..0

%e ..0..1..0..0..1..0..0....0..1..0..1..0..0..0....0..1..0..0..1..0..0

%e ..0..0..1..1..0..0..0....0..0..1..0..0..0..0....0..0..1..0..0..0..0

%e ..0..0..1..0..0..0..0....0..0..1..0..0..0..0....0..0..1..0..0..0..0

%e ..0..0..0..1..0..0..0....0..0..0..1..0..1..0....0..0..0..1..0..1..0

%e ..0..0..0..0..1..0..1....0..0..0..0..1..0..0....0..0..0..0..1..0..0

%e ..0..0..0..0..0..1..0....0..0..0..0..1..0..0....0..0..0..0..0..1..0

%e ..0..0..0..0..0..1..0....0..0..0..0..0..1..1....0..0..0..0..0..0..1

%e ..0..0..0..0..0..0..1....0..0..0..0..0..0..0....0..0..0..0..0..0..1

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

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

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

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

%Y Column 7 of A188403.

%K nonn

%O 0,2

%A _R. H. Hardin_, Mar 30 2011

%E a(0)=1 prepended and terms a(11) and beyond from _Andrew Howroyd_, Apr 07 2020