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 A189786 #14 Aug 25 2025 10:33:16
%S A189786 2,4,8,10,12,16,18,20,24,26,28,32,34,36,40,42,44,48,50,52,56,58,60,64,
%T A189786 66,68,72,74,76,80,82,84,88,90,92,96,98,100,104,106,108,112,114,116,
%U A189786 120,122,124,128,130,132,136,138,140,144,146,148,152,154,156,160,162,164,168,170,172,176,178,180,184,186,188,192,194,196,200,202,204
%N A189786 a(n) = n + [nr/t] + [ns/t]; r=Pi/2, s=arcsin(5/13), t=arcsin(12/13).
%C A189786 See A189785.
%C A189786 Conjecture: Sequence consists of all the positive even numbers except numbers of the form 8*x+6, x >= 0. - _Harvey P. Dale_, Dec 07 2018
%C A189786 Contains numbers like a(143)=382, a(146)=390, a(149)=398, a(152)=406,... which are not in A047464. - _R. J. Mathar_, Aug 25 2025
%C A189786 For n<143, a(n) = n+A047217(n+1), but then this formula becomes invalid. - _R. J. Mathar_, Aug 25 2025
%t A189786 (See A189785.)
%t A189786 With[{t=ArcSin[12/13]},Table[n+Floor[(n*Pi/2)/t]+Floor[(n*ArcSin[5/13])/t],{n,80}]] (* _Harvey P. Dale_, Dec 07 2018 *)
%Y A189786 Cf. A189785, A189787.
%K A189786 nonn,changed
%O A189786 1,1
%A A189786 _Clark Kimberling_, Apr 27 2011