This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A215781 #20 Oct 30 2024 04:27:57
%S A215781 0,1,2,3,3,4,5,6,6,7,8,9,9,10,11,11,12,13,14,14,15,16,17,17,18,19,20,
%T A215781 20,21,22,22,23,24,25,25,26,27,28,28,29,30,31,31,32,33,33,34,35,36,36,
%U A215781 37,38,39,39,40,41,41,42
%N A215781 a(n) = ceiling(n*(sqrt(3)-1)).
%C A215781 sqrt(3)-1 has continued fraction [0,1,2,1,2,1,2,...].
%H A215781 Peter G. Anderson, <a href="/A215781/b215781.txt">Table of n, a(n) for n = 0..499</a> (corrected by Ray Chandler, Jan 19 2019)
%t A215781 Table[Ceiling[n(Sqrt[3]-1)],{n,0,60}] (* _Harvey P. Dale_, Jan 15 2017 *)
%o A215781 (J) >. ( _1 + %:3) * i.500
%Y A215781 A188070 is ceiling(n/(sqrt(3)-1)).
%K A215781 nonn,easy
%O A215781 0,3
%A A215781 _Peter G. Anderson_, Aug 23 2012
%E A215781 Definition corrected by _N. J. A. Sloane_, Jan 15 2017