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 A000723 Invertible Boolean functions of n variables. (Formerly M3180 N1289) 2
 1, 3, 840, 54486432000, 68523655451482690147713024000000, 2753622660283944533494648206058191857701074569760095316814277221684346880000000000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Equivalence classes of invertible maps from {0,1}^n to {0,1}^n, under action of (C_2)^n on domain and permutation of variables on range. - Sean A. Irvine, Mar 15 2011 Also the number of distinct adjacency matrices of the n-hypercube graph Q_n. - Eric W. Weisstein, Mar 31 2017 REFERENCES M. A. Harrison, The number of classes of invertible Boolean functions, J. ACM 10 (1963), 25-28. N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..8 M. A. Harrison, The number of classes of invertible Boolean functions, J. ACM 10 (1963), 25-28. [Annotated scan of page 27 only] Eric Weisstein's World of Mathematics, Adjacency Matrix Eric Weisstein's World of Mathematics, Hypercube Graph FORMULA a(n) = (2^n-1)!/n! - Sean A. Irvine, Mar 15 2011 MATHEMATICA f[n_] := (2^n - 1)!/n!; Array[f, 6] (* Robert G. Wilson v, Mar 14 2011 *) Table[Gamma[2^n]/n!, {n, 6}] ) (* Eric W. Weisstein, Mar 31 2017 *) PROG (MAGMA) [Factorial(2^n - 1)/Factorial(n): n in [1..10]]; // Vincenzo Librandi, Mar 28 2012 CROSSREFS Sequence in context: A062658 A266654 A332183 * A020525 A252762 A283017 Adjacent sequences:  A000720 A000721 A000722 * A000724 A000725 A000726 KEYWORD nonn AUTHOR EXTENSIONS More terms from Sean A. Irvine, Mar 14 2011 STATUS approved

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Last modified May 31 19:11 EDT 2020. Contains 334748 sequences. (Running on oeis4.)