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 A275779 #13 Apr 27 2020 06:31:46
%S A275779 2,20,584,69904,34636832,69810262080,567382630219904,
%T A275779 18519084246547628288,2422583247133816584929792,
%U A275779 1268889750375080065623288448000,2659754699919401766201267083003561984,22306191045953951743035482794815064402563072
%N A275779 a(n) = (2^(n^2) - 1)/(1 - 1/2^n).
%C A275779 Sum of the geometric progression of ratio 2^n.
%C A275779 Number of all partial binary matrices with rows of length n: A partial binary matrix has 1<=k<=n rows of length n. The number of different partial matrices with k rows is 2^(k*n). a(n) is the sum for k between 1 and n.
%H A275779 Andrew Howroyd, <a href="/A275779/b275779.txt">Table of n, a(n) for n = 1..50</a>
%F A275779 a(n) = Sum_{k=1..n} 2^(k*n).
%t A275779 Table[(2^(n^2) - 1)/(1 - 1/2^n), {n, 1, 10}]
%o A275779 (PARI) a(n) = {(2^(n^2) - 1)/(1 - 1/2^n)} \\ _Andrew Howroyd_, Apr 26 2020
%Y A275779 Cf. A128889 (accepting the null matrix and excluding the full n*n matrices)
%Y A275779 Cf. A096131, A057524.
%K A275779 nonn,easy
%O A275779 1,1
%A A275779 _Olivier Gérard_, Aug 08 2016
%E A275779 Terms a(11) and beyond from _Andrew Howroyd_, Apr 26 2020