This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A032260 #19 Dec 02 2024 16:29:11 %S A032260 2,16,102,528,2470,11016,47950,205792,874998,3694920,15519262, %T A032260 64899456,270415262,1123264408,4653525150,19234571968,79342610902, %U A032260 326704870152,1343120023678,5513861152000,22606830725598,92580354402712,378737813468542,1547884976787648 %N A032260 Number of n X n (0,1) matrices such that each row and each column is nondecreasing or nonincreasing. %H A032260 Eric M. Schmidt, <a href="/A032260/b032260.txt">Table of n, a(n) for n = 1..1000</a> %H A032260 Don Coppersmith, <a href="https://research.ibm.com/haifa/ponderthis/challenges/March2004.html">Ponder This: IBM Research Monthly Puzzles, March 2004 challenge</a> %F A032260 a(n) = 2*n*(binomial(2*n, n)-n). G.f.: 4*x/(1-4*x)^(3/2)-2*x*(1+x)/(1-x)^3. - _Vladimir Baltic_ and _Vladeta Jovovic_, Jul 10 2003 %Y A032260 The number of n X n 0, 1 matrices such that each row and each column is increasing is in sequence A000984. %Y A032260 Cf. A000984, A062528, A045992, A016742, A086113 - A086115. %K A032260 nonn %O A032260 1,1 %A A032260 Yuval Dekel (dekelyuval(AT)hotmail.com), Jun 25 2003 %E A032260 Extended by _Vladimir Baltic_ and _Vladeta Jovovic_, Jul 10 2003 %E A032260 More terms from _Eric M. Schmidt_, May 01 2013