A030813 - OEIS

%I #10 Mar 16 2020 02:30:42

%S 2,4,12,48,240,1443,10105,80842,727580,7275803,80033833,960405999,

%T 12485277998,174793891980,2621908379701,41950534075224,

%U 713159079278809,12836863427018578,243900405113352992,4878008102267059852

%N a(n) = floor(exp(16/23) * n!).

%e 16/23 = 0.69565217391304347826...

%e e^(16/23) = 2.00501626694078250734215635836..., so a(1) = 2.

%e e^(16/23) * 2! = 4.01003253388156501468431271672..., so a(2) = 4.

%e e^(16/23) * 3! = 12.03009760164469504405293815..., so a(3) = 12.

%t Floor[E^(16/23) Range[20]!] (* _Alonso del Arte_, Mar 16 2020 *)

%Y Cf. A021027 (1/23).

%K nonn,easy

%O 1,1

%A _Simon Plouffe_