A022839 - OEIS

%I #33 Sep 08 2022 08:44:46

%S 2,4,6,8,11,13,15,17,20,22,24,26,29,31,33,35,38,40,42,44,46,49,51,53,

%T 55,58,60,62,64,67,69,71,73,76,78,80,82,84,87,89,91,93,96,98,100,102,

%U 105,107,109,111,114,116,118,120,122,125,127,129,131,134,136

%N Beatty sequence for sqrt(5).

%H Vincenzo Librandi, <a href="/A022839/b022839.txt">Table of n, a(n) for n = 1..10000</a>

%H R. L. Graham, S. Lin and C.-S. Lin, <a href="http://www.jstor.org/stable/2689998">Spectra of numbers</a>, Math. Mag. 51 (1978), 174-176.

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

%F a(n) = floor(n*sqrt(5)). - _G. C. Greubel_, Sep 28 2018

%p a:=n->floor(n*sqrt(5)): seq(a(n),n=1..70); # _Muniru A Asiru_, Sep 28 2018

%t With[{c=Sqrt[5]},Floor[c*Range[70]]] (* _Harvey P. Dale_, Mar 19 2012 *)

%o (Magma) [Floor(n*Sqrt(5)): n in [1..60]]; // _Vincenzo Librandi_, Oct 22 2011

%o (PARI) vector(60, n, floor(n*sqrt(5))) \\ _G. C. Greubel_, Sep 28 2018

%o (PARI) a(n)=sqrtint(5*n^2) \\ _Charles R Greathouse IV_, Jan 24 2022

%o (Python)

%o from math import isqrt

%o def A022839(n): return isqrt(5*n**2) # _Chai Wah Wu_, Sep 07 2022

%Y Cf. A026262; complement of A108598.

%K nonn,easy

%O 1,1

%A _Clark Kimberling_