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 A098871 #16 May 03 2019 17:32:03
%S A098871 1,2,5,6,17,18,21,22,65,66,69,70,81,82,85,86,257,258,261,262,273,274,
%T A098871 277,278,321,322,325,326,337,338,341,342,1025,1026,1029,1030,1041,
%U A098871 1042,1045,1046,1089,1090,1093,1094,1105,1106,1109,1110,1281,1282,1285,1286
%N A098871 Sums of distinct powers of 4 plus 1.
%H A098871 Lukasz Merta, <a href="https://arxiv.org/abs/1803.00292">Composition inverses of the variations of the Baum-Sweet sequence</a>, arXiv:1803.00292 [math.NT], 2018. See u(n) p. 11.
%F A098871 a(n) = A000695(n) + 1. - _Franklin T. Adams-Watters_, Aug 17 2013
%p A098871 a:= proc(n) local m, r, b; m, r, b:= n, 1, 1;
%p A098871 while m>0 do r:= r+b*irem(m, 2, 'm'); b:= b*4 od; r
%p A098871 end:
%p A098871 seq(a(n), n=0..100); # _Alois P. Heinz_, Aug 17 2013
%t A098871 (* first do *) Needs["DiscreteMath`Combinatorica`"]; (* then *) Take[ Sort[ Plus @@@ Subsets[ Table[4^n, {n, 0, 5}]]] + 1, 50] (* _Robert G. Wilson v_, Oct 23 2004 *)
%t A098871 Total/@Subsets[4^Range[0,5],10]+1//Union (* _Harvey P. Dale_, May 03 2019 *)
%Y A098871 Cf. A003278.
%K A098871 nonn
%O A098871 0,2
%A A098871 Tom C. Brown (tbrown(AT)sfu.ca), Oct 13 2004
%E A098871 More terms from _Robert G. Wilson v_, Oct 23 2004