A057209 - OEIS

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A057209

n!^n *sum_{k=1 to n}[1/k^k].

%I #6 Apr 09 2014 10:15:58

%S 1,5,278,428304,32130762624,179894129302241280,

%T 106668496974258140007628800,9019586503563988003191559481720832000,

%U 140893104069588516796205865279187670636282511360000

%N n!^n *sum_{k=1 to n}[1/k^k].

%e a(3) = 3!^3 *(1 +1/2^2 +1/3^3) = 6^3 *(1 +1/4 +1/27) = 278.

%K easy,nonn

%O 1,2

%A _Leroy Quet_, Sep 17 2000