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OFFSET
| 1,2
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COMMENTS
| Determinant of character table of elementary Abelian group (C_2)^n.
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 (eclark(AT)math.usf.edu), Nov 06 2003
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FORMULA
| a(n) = 2^sum(i*binomial(n, i), i=0..n) = 2^(2^(n-1)*n) - W. Edwin Clark (eclark(AT)math.usf.edu), Nov 06 2003
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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 (eclark(AT)math.usf.edu), Nov 06 2003
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CROSSREFS
| Cf. A088322.
Sequence in context: A167435 A138834 A088321 * A180962 A092798 A068916
Adjacent sequences: A061298 A061299 A061300 * A061302 A061303 A061304
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KEYWORD
| nonn,easy
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AUTHOR
| Ahmed Fares (ahmedfares(AT)my-deja.com), Jun 05 2001
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EXTENSIONS
| More terms from Jason Earls (zevi_35711(AT)yahoo.com), Jun 11 2001. Next term has 135 digits.
Edited by N. J. A. Sloane (njas(AT)research.att.com), Oct 27 2008 at the suggestion of R. J. Mathar.
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