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%I #11 Oct 26 2019 18:02:02
%S 1,1,5,12,119,135,5039,20160,240219,1545075,39916799,88550154,
%T 6227020799,42798202447,698726730520,10461394944000,355687428095999,
%U 1375276302469251,121645100408831999,845066215769150100
%N a(n) = Sum_{1<=k<=n, gcd(n,k)=1} (-1)^(n-k)*Stirling1(n,k).
%t f[n_] := Sum[ If[ GCD[n, k] == 1, (-1)^(n - k)StirlingS1[n, k], 0], {k, n}]; Table[ f[n], {n, 20}] (* _Robert G. Wilson v_, Aug 12 2004 *)
%Y Cf. A008275.
%K easy,nonn
%O 1,3
%A _Vladeta Jovovic_, Aug 01 2004
%E More terms from _Robert G. Wilson v_, Aug 12 2004
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