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 A276155 #28 Jul 07 2017 08:10:34
%S A276155 1,3,4,5,7,9,10,11,13,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,31,
%T A276155 33,34,35,37,39,40,41,43,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,
%U A276155 61,63,64,65,67,69,70,71,73,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,91,93,94,95,97,99,100,101,103,105,106,107,108,109
%N A276155 Complement of A276154; numbers that cannot be obtained by shifting left the primorial base representation (A049345) of some number.
%C A276155 The first 25 terms, when viewed in primorial base (A049345) look as: 1, 11, 20, 21, 101, 111, 120, 121, 201, 211, 220, 221, 300, 301, 310, 311, 320, 321, 400, 401, 410, 411, 420, 421, 1001.
%H A276155 Antti Karttunen, <a href="/A276155/b276155.txt">Table of n, a(n) for n = 1..10000</a>
%H A276155 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>
%t A276155 nn = 109; b = MixedRadix[Reverse@ Prime@ NestWhileList[# + 1 &, 1, Times @@ Prime@ Range[# + 1] <= nn &]]; Complement[Range@ nn, Table[FromDigits[#, b] &@ Append[IntegerDigits[n, b], 0], {n, 0, nn}]] (* Version 10.2, or *)
%t A276155 nn = 109; f[n_] := Block[{a = {{0, n}}}, Do[AppendTo[a, {First@ #, Last@ #} &@ QuotientRemainder[a[[-1, -1]], Times @@ Prime@ Range[# - i]]], {i, 0, #}] &@ NestWhile[# + 1 &, 0, Times @@ Prime@ Range[# + 1] <= n &]; Rest[a][[All, 1]]]; Complement[Range@ nn, Table[Total[Times @@@ Transpose@ {Map[Times @@ # &, Prime@ Range@ Range[0, Length@ # - 1]], Reverse@ #}] &@ Append[f@ n, 0], {n, 0, nn}]] (* _Michael De Vlieger_, Aug 26 2016 *)
%o A276155 (Scheme, with _Antti Karttunen_'s IntSeq-library)
%o A276155 (define A276155 (COMPLEMENT 1 A276154))
%Y A276155 Complement: A276154.
%Y A276155 Row 1 of A276943 and A286623. Column 1 of A276945 and A286625.
%Y A276155 Cf. A002110, A049345.
%Y A276155 Cf. A005408, A057588, A061720, A143293, A286630 (subsequences).
%Y A276155 For the first 17 terms coincides with A273670.
%K A276155 nonn,base
%O A276155 1,2
%A A276155 _Antti Karttunen_, Aug 24 2016