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 A162024 #17 Mar 26 2018 09:53:36 %S A162024 7,20,40,68,104,148,200,260,328,404,488,580,680,788,904,1028,1160, %T A162024 1300,1448,1604,1768,1940,2120,2308,2504,2708,2920,3140,3368,3604, %U A162024 3848,4100,4360,4628,4904,5188,5480,5780,6088,6404,6728,7060,7400,7748,8104,8468 %N A162024 Number of n X n binary arrays with rows and columns, considered as binary numbers, in nondecreasing order, and all but the outermost row or column zero. %H A162024 R. H. Hardin, <a href="/A162024/b162024.txt">Table of n, a(n) for n = 2..100</a> %F A162024 Empirical: a(n)= 3*a(n-1) - 3*a(n-2) + a(n-3), n>5. a(n)= A128445(n+1), n>2. - _R. J. Mathar_, Aug 11 2009 %F A162024 Conjectures from _Colin Barker_, Mar 24 2018: (Start) %F A162024 G.f.: x^2*(7 - x + x^2 + x^3) / (1 - x)^3. %F A162024 a(n) = 4*(2 - 2*n + n^2) for n>2. %F A162024 (End) %K A162024 nonn %O A162024 2,1 %A A162024 _R. H. Hardin_, Jun 25 2009