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 A347212 #43 Jun 11 2023 23:29:15
%S A347212 1,2,3,6,11,18,36,69,131,258,522,1025,2054,4101,8194,16394,32817,
%T A347212 65542,131085,262183,524313,1048588,2097164,4194310,8388624,16777218,
%U A347212 33554433,67108881,134217730,268435473,536870927,1073741861
%N A347212 a(n) is the next Ulam number (A002858) after 2^(n-1).
%C A347212 This sequence appears to be a "complete" (sic) sequence as defined in the Wikipedia link.
%H A347212 Wikipedia, <a href="http://en.wikipedia.org/wiki/Complete_sequence">"Complete" sequence</a>. [Wikipedia calls a sequence "complete" (sic) if every positive integer is a sum of distinct terms. This name is extremely misleading and should be avoided. - _N. J. A. Sloane_, May 20 2023]
%e A347212 a(0) = 1 because 1 is the next Ulam number after 2^(-1) = 1/2.
%e A347212 a(6) = 36 because 36 is the next Ulam number after 2^5 = 32.
%t A347212 ulams={1, 2}; Do[AppendTo[ulams, n=Last[ulams]; While[n++; Length[DeleteCases[Intersection[ulams, n-ulams], n/2, 1, 1]]!= 2]; n], {10^4}]; lst=ulams; nextu[n_] := Module[{m = 1}, While[lst[[m]]<=n, m++]; lst[[m]]]; Join[{1}, Table[nextu[2^(n - 1)], {n, 1, 18}]]
%Y A347212 Cf. A002858, A331729.
%K A347212 nonn,more
%O A347212 0,2
%A A347212 _Frank M Jackson_, Sep 02 2021
%E A347212 a(22)-a(31) from _Amiram Eldar_, Sep 02 2021