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 A153787 #13 Nov 26 2019 04:23:51
%S A153787 1,2,3,7,17,1,19,167,1094,2899,1,13945,56817,155286,284489,785593,
%T A153787 3268191,9099642,16950673,47515853,133587741,376586805,1064242599,
%U A153787 1291914643,12834909238,36503886401,1944142787,19152993059,1144562017
%N A153787 Largest proper divisor of Motzkin number A001006(n).
%H A153787 Amiram Eldar, <a href="/A153787/b153787.txt">Table of n, a(n) for n = 2..200</a>
%p A153787 with(numtheory): M := proc (n) options operator, arrow: (sum((-1)^j*binomial(n+1, j)*binomial(2*n-3*j, n), j = 0 .. floor((1/3)*n)))/(n+1) end proc: seq(divisors(M(i))[tau(M(i))-1], i = 2 .. 32); # _Emeric Deutsch_, Jan 18 2009
%t A153787 mot[0] = 1; mot[n_] := mot[n] = mot[n - 1] + Sum[mot[k] * mot[n - 2 - k], {k, 0, n - 2}]; lpd[n_] := n / FactorInteger[n][[1, 1]]; Table[lpd[mot[n]], {n, 2, 30}] (* _Amiram Eldar_, Nov 26 2019 *)
%Y A153787 Cf. A001006, A032742, A152766, A152982.
%K A153787 nonn
%O A153787 2,2
%A A153787 _Omar E. Pol_, Jan 16 2009
%E A153787 Extended by _Emeric Deutsch_, Jan 18 2009
%E A153787 a(23)-a(27) and a(29)-a(30) corrected by _Amiram Eldar_, Nov 26 2019