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a(n) = A000178(n) * Sum_{k=0..n} (-1)^k/k!.
1

%I #9 Dec 22 2016 23:36:43

%S 1,0,1,4,108,12672,9158400,46133452800,1860226228224000,

%T 675033837113180160000,2449564623049780415692800000,

%U 97778774486746890792389836800000000,46836189690981206780971946461888512000000000,291649927271171583734813938085106400257638400000000000

%N a(n) = A000178(n) * Sum_{k=0..n} (-1)^k/k!.

%H Daniel Suteu, <a href="/A279046/b279046.txt">Table of n, a(n) for n = 0..19</a>

%F a(n) ~ A000178(n) / e.

%F a(0) = 1, a(n) = n! * a(n-1) + (-1)^n * A000178(n-1).

%Y Cf. A000178.

%K nonn,easy

%O 0,4

%A _Daniel Suteu_, Dec 04 2016