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 A243835 #9 Feb 03 2019 07:39:42 %S A243835 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, %T A243835 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4862,0,0,0,0,0,0,0,0,0,4862, %U A243835 0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,45,0,0,0,0,0,0,0,0,0,0,0,0,1,825,0,0,0,0,0,0,0,0,0,0,0,0,0,55,9075,0,0 %N A243835 Number A(n,k) of Dyck paths of semilength n having exactly nine (possibly overlapping) occurrences of the consecutive step pattern given by the binary expansion of k, where 1=U=(1,1) and 0=D=(1,-1); square array A(n,k), n>=0, k>=0, read by antidiagonals. %H A243835 Alois P. Heinz, <a href="/A243835/b243835.txt">Antidiagonals n = 0..140, flattened</a> %e A243835 Square array A(n,k) begins: %e A243835 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A243835 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A243835 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A243835 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A243835 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A243835 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A243835 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A243835 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A243835 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A243835 4862, 4862, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A243835 0, 0, 45, 1, 0, 1, 0, 0, 0, 0, 1, 0, ... %e A243835 0, 0, 825, 55, 0, 10, 0, 1, 0, 0, 1, 0, ... %Y A243835 Main diagonal gives A243778 or column k=9 of A243752. %Y A243835 Cf. A243753, A243827, A243828, A243829, A243830, A243831, A243832, A243833, A243834, A243836. %K A243835 nonn,tabl %O A243835 0,55 %A A243835 _Alois P. Heinz_, Jun 11 2014