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 A308846 #10 Jul 03 2019 04:07:57
%S A308846 1,-1,0,2,-1,-11,11,125,-181,-2443,4534,73116,-164075,-3106169,
%T A308846 8150624,177689590,-533231545,-13167063415,44461467464,1226832808294,
%U A308846 -4603245727023,-140381127928757,579412786145335,19352381237997941,-87137414891475575,-3163451350469601721,15431005593881754746
%N A308846 Expansion of e.g.f. x*exp(-x) / BesselI(1,2*x).
%C A308846 E.g.f. is inverse of e.g.f. for A001006 (Motzkin numbers).
%F A308846 E.g.f.: 1 / Sum_{k>=0} A001006(k)*x^k/k!.
%t A308846 nmax = 26; CoefficientList[Series[x Exp[-x]/BesselI[1, 2 x], {x, 0, nmax}], x] Range[0, nmax]!
%t A308846 a[0] = 1; a[n_] := a[n] = -Sum[Binomial[n, k] Hypergeometric2F1[(1 - k)/2, -k/2, 2, 4] a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 26}]
%o A308846 (PARI) my(x='x+O('x^30)); Vec(serlaplace(exp(-x) / besseli(1,2*x))) \\ _Michel Marcus_, Jul 02 2019
%Y A308846 Cf. A001006, A292440.
%K A308846 sign
%O A308846 0,4
%A A308846 _Ilya Gutkovskiy_, Jun 28 2019