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 A357309 #8 Sep 23 2022 12:12:42 %S A357309 1,1,6,54,660,10255,193732,4312980,110598510,3210608808,104085718451, %T A357309 3727491264497,146140031249576,6225801069767760,286376011804522536, %U A357309 14145748008085964988,746808042116142422388,41964968782188114180606,2500755433211714966201145 %N A357309 Number of ascent sequences of length 2n with n zeros. %H A357309 Alois P. Heinz, <a href="/A357309/b357309.txt">Table of n, a(n) for n = 0..100</a> %F A357309 a(n) = A175579(2n,n). %e A357309 a(2) = 4: 0011, 0012, 0101, 0102, 0110, 0120. %Y A357309 Cf. A175579. %K A357309 nonn %O A357309 0,3 %A A357309 _Alois P. Heinz_, Sep 23 2022