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 A183866 #6 Mar 30 2012 18:57:13
%S A183866 1,4,5,7,9,10,11,13,14,16,17,18,19,21,22,23,25,26,27,28,29,31,32,33,
%T A183866 34,36,37,38,39,40,41,43,44,45,46,47,49,50,51,52,53,54,55,57,58,59,60,
%U A183866 61,62,64,65,66,67,68,69,70,71,73,74,75,76,77,78,79,81,82,83,84,85,86,87,88,89,91,92,93,94,95,96,97,98,100,101,102,103,104,105,106,107,108,109,111,112,113,114,115,116,117,118,119
%N A183866 n+floor(2*sqrt(n-1)); complement of A035106.
%t A183866 a=4; b=-4;
%t A183866 Table[n+Floor[(a*n+b)^(1/2)],{n,100}]
%t A183866 Table[n-1+Ceiling[(n*n-b)/a],{n,70}]
%Y A183866 Cf. A035106.
%K A183866 nonn,easy
%O A183866 1,2
%A A183866 _Clark Kimberling_, Jan 07 2011