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a(n) = n^2*2^(n^2-1).
2

%I #12 May 08 2023 15:08:24

%S 0,1,32,2304,524288,419430400,1236950581248,13792273858822144,

%T 590295810358705651712,97922991388784963151200256,

%U 63382530011411470074835160268800

%N a(n) = n^2*2^(n^2-1).

%C a(n) is the number of elements (ordered pairs) in all binary relations on {1,2,...,n}.

%C Equivalently a(n) is the number of 1's in all n X n {0,1} matrices.

%H G. C. Greubel, <a href="/A185968/b185968.txt">Table of n, a(n) for n = 0..57</a>

%t Table[n^2 *2^(n^2-1),{n,0,10}]

%o (PARI) for(n=0,25, print1(n^2 *2^(n^2-1), ", ")) \\ _G. C. Greubel_, Jul 23 2017

%Y Cf. A175716.

%K nonn

%O 0,3

%A _Geoffrey Critzer_, Feb 07 2011

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Last modified September 21 11:10 EDT 2024. Contains 376084 sequences. (Running on oeis4.)