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 A055066 #20 Feb 28 2023 21:09:17 %S A055066 1,7,62,664,8609,127415,2004975,31500927,474504448,6708348262, %T A055066 88249739792,1078567590128,12269901302433,130370516668917, %U A055066 1298891291366245,12182760243381355,107979270564656625,907568508195185203,7256984238345563764,55365443728411530716,404091280028746802188 %N A055066 Number of 7-covers of an unlabeled n-set. %C A055066 Number of 7 X n binary matrices with at least one 1 in every column up to row and column permutations. - _Andrew Howroyd_, Feb 28 2023 %H A055066 Andrew Howroyd, <a href="/A055066/b055066.txt">Table of n, a(n) for n = 0..1000</a> %H A055066 Vladeta Jovovic, <a href="/A005748/a005748.pdf">Binary matrices up to row and column permutations</a> %o A055066 (PARI) Vec(G(7, x)*(1-x) + O(x^40)) \\ G defined in A028657. - _Andrew Howroyd_, Feb 28 2023 %Y A055066 Column 7 of A055080. %Y A055066 Cf. A005748, A002620, A005783, A005784, A005785, A005786. %K A055066 nonn %O A055066 0,2 %A A055066 _Vladeta Jovovic_, Jun 12 2000 %E A055066 a(0)=1 prepended by _Alois P. Heinz_, Aug 08 2022 %E A055066 Terms a(17) and beyond from _Andrew Howroyd_, Feb 28 2023