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a(n) = floor(n*(sqrt(5)+sqrt(3))).
15

%I #21 Sep 08 2022 08:45:50

%S 0,3,7,11,15,19,23,27,31,35,39,43,47,51,55,59,63,67,71,75,79,83,87,91,

%T 95,99,103,107,111,115,119,123,126,130,134,138,142,146,150,154,158,

%U 162,166,170,174,178,182,186,190,194,198,202,206,210,214,218

%N a(n) = floor(n*(sqrt(5)+sqrt(3))).

%C sqrt(5)+sqrt(3) = 3.96811878506867... is the largest root of x^4 - 16*x^2 + 4.

%H Vincenzo Librandi, <a href="/A172338/b172338.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Be#Beatty">Index entries for sequences related to Beatty sequences</a>

%t With[{c = Sqrt[5] + Sqrt[3]}, Floor[c Range[0,60]]] (* _Harvey P. Dale_, Apr 10 2012 *)

%o (Magma) [Floor(n*Sqrt(5)+Sqrt(3)): n in [0..60] ];

%o (PARI) a(n)=sqrtint(sqrtint(60*n^4)+8*n^2) \\ _Charles R Greathouse IV_, Jan 24 2022

%Y Cf. A110117, A172323-A172332, A172334, A172336, A172337.

%K nonn,less,easy

%O 0,2

%A _Vincenzo Librandi_, Feb 01 2010