Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #11 Dec 01 2023 03:25:52
%S 1,1,1,1,2,1,1,3,3,1,1,4,7,4,1,1,5,14,14,5,1,1,6,25,45,25,6,1,1,7,41,
%T 130,130,41,7,1,1,8,63,336,650,336,63,8,1,1,9,92,785,2942,2942,785,92,
%U 9,1,1,10,129,1682,11819,24520,11819,1682,129,10,1,1,11,175
%N Square array of number of distinct m X n (0,1) matrices after iterated double sorting, read by antidiagonals.
%C T(m,n) gives the number of distinct results obtained by repeatedly sorting the m X n (0,1) matrices by columns & then rows until reaching a fixed point. Its diagonal is A089006.
%e Array begins:
%e 1,1,1,1,1,...
%e 1,2,3,4,5,...
%e 1,3,7,14,25,...
%e 1,4,14,45,130,...
%e 1,5,25,130,650,...
%o (Haskell)
%o -- with the function "t" producing the array.
%o import List
%o prod = foldr (\x xs -> [y:ys | y <- x, ys <- xs]) [[]]
%o f xs = let ys = sort (transpose (sort (transpose xs))) in if xs == ys then xs else f ys
%o t m n = length $ nub $ map f $ prod (replicate m (prod (replicate n [0,1])))
%Y Cf. A089006.
%K nonn,tabl
%O 0,5
%A Randy Compton (RANDYRulerOfZexernet(AT)gmail.com), Dec 15 2009
%E Corrected & extended by Randy Compton (RANDYRulerOfZexernet(AT)gmail.com), Dec 18 2009