cp's OEIS Frontend

A184004 a(n) = n + floor(sqrt(4n/3)); complement of A184005.

%I A184004 #20 Oct 01 2024 04:20:23
%S A184004 2,3,5,6,7,8,10,11,12,13,14,16,17,18,19,20,21,22,24,25,26,27,28,29,30,
%T A184004 31,33,34,35,36,37,38,39,40,41,42,44,45,46,47,48,49,50,51,52,53,54,56,
%U A184004 57,58,59,60,61,62,63,64,65,66,67,68,70,71,72,73,74,75,76,77,78,79,80,81,82,83,85,86,87,88,89,90
%N A184004 a(n) = n + floor(sqrt(4n/3)); complement of A184005.
%H A184004 G. C. Greubel, <a href="/A184004/b184004.txt">Table of n, a(n) for n = 1..5000</a>
%t A184004 a=4/3; b=0;
%t A184004 Table[n+Floor[(a*n+b)^(1/2)],{n,80}]
%t A184004 Table[n-1+Ceiling[(n*n-b)/a],{n,60}]
%o A184004 (PARI) for(n=1, 100, print1(n + floor(sqrt(4*n/3)), ", ")) \\ _G. C. Greubel_, Jul 22 2017
%o A184004 (PARI) a(n) = n + sqrtint(4*n/3); \\ _Michel Marcus_, Oct 01 2024
%o A184004 (Python)
%o A184004 from math import isqrt
%o A184004 def A184004(n): return n+isqrt((n<<2)//3) # _Chai Wah Wu_, Oct 01 2024
%Y A184004 Cf. A184005.
%K A184004 nonn,easy
%O A184004 1,1
%A A184004 _Clark Kimberling_, Jan 08 2011