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 A264663 #12 Feb 16 2025 08:33:27
%S A264663 1,1,10,101,1110,101010,10000100,110101101,10110010110,1001011111110,
%T A264663 100000110011100,1110010110100010,110010110010001100,
%U A264663 10110101010111110100,1010001100111100001000,100100111110111001111101,10000110111000001111100110,111101110100011100011110110,11100011110000011000000101100
%N A264663 Catalan numbers written in base 2.
%H A264663 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CatalanNumber.html">Catalan Number</a>
%H A264663 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Binary.html">Binary</a>
%F A264663 a(n) = A007088(A000108(n)).
%t A264663 Table[FromDigits[IntegerDigits[CatalanNumber[n], 2]], {n, 0, 18}]
%o A264663 (PARI) vector(30, n, n--; subst(Pol(binary(binomial(2*n,n)/(n+1))), 'x, 10)) \\ _Altug Alkan_, Nov 20 2015
%o A264663 (Magma) [Seqint(Intseq(Catalan(n), 2)): n in [0..20]]; // _Vincenzo Librandi_, Nov 21 2015
%Y A264663 Cf. A000108, A004676, A004685.
%K A264663 nonn,base
%O A264663 0,3
%A A264663 _Ilya Gutkovskiy_, Nov 20 2015