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 A134717 #19 Aug 26 2024 04:58:26
%S A134717 1,1,9,21,51,127,323,835,15511,41835,853467,2356779,50852019,
%T A134717 142547559,400763223,1129760415,3192727797,9043402501,208023278209,
%U A134717 593742784829,1697385471211,4859761676391,13933569346707,40002464776083,953467954114363,2750016719520991,7939655757745265
%N A134717 Odd Motzkin numbers.
%C A134717 A001006 except A134718. - _Vladimir Reshetnikov_, Nov 02 2015
%C A134717 The asymptotic density of this sequence within the Motzkin numbers is 2/3. - _Amiram Eldar_, Aug 26 2024
%H A134717 Robert Israel, <a href="/A134717/b134717.txt">Table of n, a(n) for n = 1..801</a>
%F A134717 a(n) = A001006(A161674(n)). - _Amiram Eldar_, Aug 26 2024
%p A134717 S:= series(exp(x)*BesselI(1, 2*x)/x, x, 500):
%p A134717 select(type, [seq(simplify(coeff(S,x,j)*j!), j=0..498)], odd); # _Robert Israel_, Nov 03 2015
%t A134717 Select[Table[(-1)^n Hypergeometric2F1[3/2, -n, 3, 4], {n, 0, 40}], OddQ] (* _Vladimir Reshetnikov_, Nov 02 2015 *)
%o A134717 (PARI) a001006(n) = polcoeff((1-x-sqrt((1-x)^2-4*x^2+x^3*O(x^n)))/ (2*x^2), n); for(n=0, 100, if((m=a001006(n))%2==1, print1(m", "))) \\ _Altug Alkan_, Nov 03 2015
%Y A134717 Cf. A001006, A134718, A161674.
%K A134717 easy,nonn
%O A134717 1,3
%A A134717 _Omar E. Pol_, Nov 11 2007