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 A048719 #15 Jan 01 2021 11:23:34
%S A048719 0,3,6,12,24,48,51,96,99,102,192,195,198,204,384,387,390,396,408,768,
%T A048719 771,774,780,792,816,819,1536,1539,1542,1548,1560,1584,1587,1632,1635,
%U A048719 1638,3072,3075,3078,3084,3096
%N A048719 Binary expansion matches ((0)*0011)*(0*).
%C A048719 1-bits occur only in pairs, separated from other such pairs by at least two 0-bits.
%C A048719 All terms satisfy both A048727(n) = 3*n and A048725(n) = 5*n.
%H A048719 <a href="/index/Con#CongruCrossDomain">Index entries for sequences defined by congruent products between domains N and GF(2)[X]</a>
%F A048719 a(n) = 3*A048718(n).
%t A048719 filterQ[n_] := With[{bb = IntegerDigits[n, 2]}, !MatchQ[bb, {1}|{1, 0, ___}|{___, 0, 1}|{___, 0, 1, 0, ___}|{___, 1, 1, 1, ___}|{___, 1, 0, 1, ___}]];
%t A048719 Select[Range[0, 3096], filterQ] (* _Jean-François Alcover_, Dec 31 2020 *)
%o A048719 (PARI) is(n)=n%3==0 && !bitand(n/3, 14*n/3) \\ _Charles R Greathouse IV_, Oct 03 2016
%Y A048719 Intersection of A048716 and A048717.
%K A048719 nonn,base,easy
%O A048719 0,2
%A A048719 _Antti Karttunen_, Mar 30 1999