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 A183292 #7 Jan 20 2016 11:58:42
%S A183292 1,2,3,5,6,7,8,10,11,12,13,14,16,17,18,19,20,21,23,24,25,26,27,28,29,
%T A183292 31,32,33,34,35,36,37,38,40,41,42,43,44,45,46,47,48,50,51,52,53,54,55,
%U A183292 56,57,58,59,61,62,63,64,65,66,67,68,69,70,71,73,74,75,76,77,78,79,80,81,82,83,84,86,87,88,89,90
%N A183292 Complement of A055999.
%F A183292 (See the Mathematica code.)
%t A183292 a=1/2; b=7/2;
%t A183292 F[n_]:=a*n^2+b*n;
%t A183292 R[n_]:=(n/a+((b-1)/(2a))^2)^(1/2);
%t A183292 G[n_]:=n-1+Ceiling[R[n]-(b-1)/(2a)];
%t A183292 Table[F[n], {n,60}]
%t A183292 Table[G[n], {n,100}]
%o A183292 (PARI) a(n)=n-1+ceil(sqrt(8*n+25)/2-5/2) \\ _Charles R Greathouse IV_, Jan 20 2016
%Y A183292 Cf. A055999.
%K A183292 nonn
%O A183292 1,2
%A A183292 _Clark Kimberling_, Jan 03 2011