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 A171368 #10 Oct 20 2023 07:29:13
%S A171368 1,0,0,1,0,0,0,1,0,0,2,0,1,0,0,0,5,0,1,0,0,5,0,9,0,1,0,0,0,21,0,14,0,
%T A171368 1,0,0,14,0,56,0,20,0,1,0,0,0,84,0,120,0,27,0,1,0,0,42,0,300,0,225,0,
%U A171368 35,0,1,0,0,0,330,0,825,0,385,0,44,0,1,0,0
%N A171368 Another version of A126216.
%C A171368 Expansion of the first column of the triangle T_(0,x), T_(x,y) defined in A039599; T_(0,0)= A053121, T_(0,1)= A089942, T_(0,2)= A126093, T_(0,3)= A126970.
%C A171368 T(n,k) is the number of Riordan paths of length n with k horizontal steps. A Riordan path is a Motzkin path with no horizontal steps on the x-axis. - _Emanuele Munarini_, Oct 14 2023
%F A171368 Sum_{k, 0<=k<=n} T(n,k)*x^k = A099323(n+1), A126120(n), A005043(n), A000957(n+1), A117641(n) for x = -1, 0, 1, 2, 3 respectively.
%e A171368 Triangle begins:
%e A171368 1 ;
%e A171368 0,0 ;
%e A171368 1,0,0 ;
%e A171368 0,1,0,0 ;
%e A171368 2,0,1,0,0 ;
%e A171368 0,5,0,1,0,0 ;
%e A171368 5,0,9,0,1,0,0 ;
%e A171368 ...
%Y A171368 Cf. A000108, A001003,
%K A171368 nonn,tabl
%O A171368 0,11
%A A171368 _Philippe Deléham_, Dec 06 2009