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%I #9 May 10 2013 12:45:34
%S 0,1,42,15654,1073421588,4611685989440629944,
%T 85070591730234615704434641716516893512,
%U 28948022309329048855892746252171976959574390130279817915318273546782086570304
%N Number of proper T_0-covers of an n-set.
%C The next term has 154 decimal digits.
%F a(n) = Sum(Stirling1(n, k)*A007537(k), k=1..n).
%F a(n) = Sum((2*Stirling1(n+1, k+1)-Stirling1(n, k))*2^(2^k-2), k=0..n).
%o (PARI)
%o a(n)=sum(k=0,n, (2*stirling(n+1, k+1, 1) - stirling(n, k,1 )) * 2^(2^k-2) );
%o vector(10,n,a(n)) /* show terms */
%Y Row sums of A095422, A095421.
%K easy,nonn
%O 1,3
%A Goran Kilibarda, _Vladeta Jovovic_, Jun 04 2004
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