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a(n) = Floor(e*sqrt(n)).
16

%I #17 Sep 08 2022 08:45:27

%S 0,2,3,4,5,6,6,7,7,8,8,9,9,9,10,10,10,11,11,11,12,12,12,13,13,13,13,

%T 14,14,14,14,15,15,15,15,16,16,16,16,16,17,17,17,17,18,18,18,18,18,19,

%U 19,19,19,19,19,20,20,20,20,20,21,21,21,21,21,21,22,22,22,22,22,22,23,23

%N a(n) = Floor(e*sqrt(n)).

%H Vincenzo Librandi, <a href="/A121856/b121856.txt">Table of n, a(n) for n = 0..1000</a>

%t Floor[E Sqrt[Range[0,80]]] (* _Harvey P. Dale_, May 16 2012 *)

%o (PARI) for(n=0,50, print1(floor(exp(1)*sqrt(n)), ", ")) \\ _G. C. Greubel_, Oct 28 2017

%o (Magma) [Floor(Exp(1)*Sqrt(n)): n in [0..50]]; // _G. C. Greubel_, Oct 28 2017

%Y Cf. A121275, A121276.

%K nonn

%O 0,2

%A _Mohammad K. Azarian_, Aug 30 2006

%E Offset corrected by _Harvey P. Dale_, May 16 2012