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 A048973 #14 Oct 22 2016 02:57:34
%S A048973 4,7,9,12,13,15,20,23,26,27,28,31,36,38,39,42,44,48,50,52,53,55,56,61,
%T A048973 63,64,66,74,79,83,85,89,98,101,103,107,109,114,120,123,125,128,131,
%U A048973 133,136,144,152,157,159,160,165,168,182,184,190,192,198,203,208,212
%N A048973 Complement of A005243.
%C A048973 The sequence appears to be growing slightly faster than quadratically. - _T. D. Noe_, Nov 04 2007
%H A048973 T. D. Noe, <a href="/A048973/b048973.txt">Table of n, a(n) for n=1..6564</a> (terms < 10^8)
%t A048973 nmax = 250; For[ s = {1, 2}; n = 3, n <= nmax, n++, ls = Length[s]; tt = Total /@ Flatten[Table[s[[i ;; j]], {i, 1, ls - 1}, {j, i + 1, ls}], 1]; If[MemberQ[tt, n], AppendTo[s, n]]]; A048973 = Complement[Range[nmax], s] (* _Jean-François Alcover_, Oct 21 2016 *)
%o A048973 (Haskell)
%o A048973 import Data.List.Ordered (minus)
%o A048973 a048973 n = a048973_list !! (n-1)
%o A048973 a048973_list = [1..] `minus` a005243_list
%o A048973 -- _Reinhard Zumkeller_, Dec 17 2015
%K A048973 nonn,easy,nice
%O A048973 1,1
%A A048973 D. R. Hofstadter
%E A048973 More terms from Larry Reeves (larryr(AT)acm.org), Oct 02 2000