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 A061301 a(n) = 2^(n*2^(n-1)). 4
 1, 2, 16, 4096, 4294967296, 1208925819614629174706176, 6277101735386680763835789423207666416102355444464034512896 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Determinant of character table of elementary Abelian group (C_2)^n. a(7) has 135 digits. - Jason Earls, Jun 11 2001 Number of functions f:2^X->2^X where X is an n-element set such that f(A) is a subset of A for all A in 2^X (where 2^X denotes the power set of X). - W. Edwin Clark, Nov 06 2003 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..9 F. Echenique, Counting Combinatorial Choice Rules, Games and Economic Behavior, Vol. 58, No. 2 (2007), 231-245. Lara Pudwell, Nathan Chenette, Manda Riehl, Statistics on Hypercube Orientations, AMS Special Session on Experimental and Computer Assisted Mathematics, Joint Mathematics Meetings (Denver 2020). FORMULA a(n) = 2^Sum_{i=0..n} i*binomial(n, i) = 2^(2^(n-1)*n). - W. Edwin Clark, Nov 06 2003 EXAMPLE a(2) = 16 because the character table for C_2 X C_2 is / 1 1 1 1 / 1 -1 -1 1 / 1 -1 1 -1 / 1 1-1 -1 / with determinant 16 = (2^2)^(2^1). a(1) = 2 since 2^{1} = { {}, {1}} and the functions f : 2^{1}->2^{1} satisfying f(A) is a subset of A for all A are g and h where g({})={}, g({1})={} and h({}) = {}, h({1})={1}. - W. Edwin Clark, Nov 06 2003 MATHEMATICA Table[2^(n 2^(n - 1)), {n, 0, 7}] (* Vincenzo Librandi, Sep 02 2018 *) PROG (MAGMA) [2^(n*2^(n-1)): n in [0..5]]; // Vincenzo Librandi, Sep 02 2018 CROSSREFS Cf. A088322. Sequence in context: A270124 A138834 A088321 * A180962 A324565 A306729 Adjacent sequences:  A061298 A061299 A061300 * A061302 A061303 A061304 KEYWORD nonn,easy AUTHOR Ahmed Fares (ahmedfares(AT)my-deja.com), Jun 05 2001 EXTENSIONS More terms from Jason Earls, Jun 11 2001 Edited by N. J. A. Sloane, Oct 27 2008 at the suggestion of R. J. Mathar Offset changed to 0 by Vincenzo Librandi, Sep 02 2018 STATUS approved

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Last modified August 1 07:45 EDT 2021. Contains 346384 sequences. (Running on oeis4.)