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 A005786 M4244 #25 Feb 28 2023 21:09:23 %S A005786 1,6,43,336,2864,25326,223034,1890123,15115098,112980937,787320629, %T A005786 5121184083,31188412225,178517111561,964196387369,4933278065881, %U A005786 23997707450765,111358094980387,494444748602595,2106504840061571 %N A005786 Number of 6-covers of an unlabeled n-set. %C A005786 Number of 6 X n binary matrices with at least one 1 in every column up to row and column permutations. %D A005786 R. J. Clarke, Covering a set by subsets, Discrete Math., 81 (1990), 147-152. %D A005786 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A005786 Andrew Howroyd, <a href="/A005786/b005786.txt">Table of n, a(n) for n = 0..500</a> %H A005786 Vladeta Jovovic, <a href="/A005748/a005748.pdf">Binary matrices up to row and column permutations</a> %o A005786 (PARI) Vec(G(6, x)*(1 - x) + O(x^40)) \\ G defined in A028657. - _Andrew Howroyd_, Feb 28 2023 %Y A005786 Column 6 of A055080. %Y A005786 Cf. A002620, A005783, A005784, A005785, A055066. %K A005786 nonn %O A005786 0,2 %A A005786 _N. J. A. Sloane_ %E A005786 More terms from _Vladeta Jovovic_, Jun 12 2000 %E A005786 a(0)=1 prepended by _Alois P. Heinz_, Aug 08 2022