# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a005747 Showing 1-1 of 1 %I A005747 M5018 #22 Feb 28 2023 22:25:11 %S A005747 1,16,196,2197,22952,223034,2004975,16642937,127654604,907349654, %T A005747 6000728764,37093282121,215296646264,1178514299094,6108871834312, %U A005747 30098215339608,141433252447082,635816643771438,2742163498527536,11374522802412498,45482770393453638 %N A005747 Number of n-covers of an unlabeled 6-set. %C A005747 Number of n X 6 binary matrices with at least one 1 in every column up to row and column permutations. - _Andrew Howroyd_, Feb 28 2023 %D A005747 R. J. Clarke, Covering a set by subsets, Discrete Math., 81 (1990), 147-152. %D A005747 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A005747 Andrew Howroyd, Table of n, a(n) for n = 1..1000 %H A005747 Vladeta Jovovic, Binary matrices up to row and column permutations %o A005747 (PARI) Vec((G(6, x) - G(5, x)) + O(x^30)) \\ G defined in A028657. - _Andrew Howroyd_, Feb 28 2023 %Y A005747 A diagonal of A055080. %Y A005747 First differences give A055084. %K A005747 nonn %O A005747 1,2 %A A005747 _N. J. A. Sloane_, _Simon Plouffe_ %E A005747 Corrected and extended by _Vladeta Jovovic_, Jun 13 2000 %E A005747 Terms a(20) and beyond from _Andrew Howroyd_, Feb 28 2023 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE