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A225982 T(n,k)=Number of nXk binary arrays whose sum with another nXk binary array containing no more than two 1s has rows and columns in lexicographically nondecreasing order.

%I A225982 #6 Jul 23 2025 05:26:18
%S A225982 2,4,4,8,15,8,15,48,48,15,26,138,252,138,26,42,350,1178,1178,350,42,
%T A225982 64,790,4722,9113,4722,790,64,93,1616,16361,61808,61808,16361,1616,93,
%U A225982 130,3049,49811,361361,737893,361361,49811,3049,130,176,5384,135672,1825607
%N A225982 T(n,k)=Number of nXk binary arrays whose sum with another nXk binary array containing no more than two 1s has rows and columns in lexicographically nondecreasing order.
%C A225982 Table starts
%C A225982 ...2....4......8........15..........26............42.............64
%C A225982 ...4...15.....48.......138.........350...........790...........1616
%C A225982 ...8...48....252......1178........4722.........16361..........49811
%C A225982 ..15..138...1178......9113.......61808........361361........1825607
%C A225982 ..26..350...4722.....61808......737893.......7718077.......69784592
%C A225982 ..42..790..16361....361361.....7718077.....148890101.....2513743785
%C A225982 ..64.1616..49811...1825607....69784592....2513743785....80901937149
%C A225982 ..93.3049.135672...8065278...546720823...36836074434..2279339811483
%C A225982 .130.5384.336189..31631401..3748375290..470279869497.56056577764123
%C A225982 .176.9001.768900.111785599.22776885553.5279223820491
%H A225982 R. H. Hardin, <a href="/A225982/b225982.txt">Table of n, a(n) for n = 1..127</a>
%F A225982 Empirical: columns k=1..5 are polynomials in n of degree 2^k+1 for n>0,0,1,2,2
%e A225982 Some solutions for n=3 k=4
%e A225982 ..0..0..1..1....0..0..1..1....0..1..1..0....1..1..1..1....0..0..1..1
%e A225982 ..1..1..1..1....1..1..0..0....0..1..1..0....1..1..1..1....0..0..0..1
%e A225982 ..1..0..0..1....0..0..0..1....1..0..0..0....1..0..1..0....1..1..1..1
%Y A225982 Column 1 is A000125
%K A225982 nonn,tabl
%O A225982 1,1
%A A225982 _R. H. Hardin_ May 22 2013