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 A335749 #18 Feb 01 2024 08:19:07
%S A335749 1,8,34,152,676,3008,13384,59552,264976,1179008,5245984,23341952,
%T A335749 103859776,462123008,2056211584,9149092352,40708792576,181133355008,
%U A335749 805951005184,3586070730752,15956184933376,70996881195008,315899894646784,1405593340977152,6254173153202176
%N A335749 a(n) = n!*[x^n] exp(2*x)*(y*sinh(x*y) + cosh(x*y)) and y = sqrt(6).
%H A335749 Colin Barker, <a href="/A335749/b335749.txt">Table of n, a(n) for n = 0..1000</a>
%H A335749 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (4,2).
%F A335749 a(n) = A335312(n, 6).
%F A335749 From _Colin Barker_, Jun 24 2020: (Start)
%F A335749 G.f.: (1 + 4*x) / (1 - 4*x - 2*x^2) for n>1.
%F A335749 a(n) = 4*a(n-1) + 2*a(n-2). (End)
%F A335749 a(n) = 4*A090017(n)+A090017(n+1). - _R. J. Mathar_, Mar 10 2022
%p A335749 aList := proc(len) local H; H := (x, y) -> exp(2*x)*(y*sinh(x*y) + cosh(x*y)):
%p A335749 series(H(x, sqrt(6)), x, len + 1): seq(k!*coeff(%, x, k), k=0..len-1) end:
%p A335749 aList(25);
%t A335749 LinearRecurrence[{4, 2}, {1, 8}, 30] (* _Paolo Xausa_, Feb 01 2024 *)
%o A335749 (PARI) Vec((1 + 4*x) / (1 - 4*x - 2*x^2) + O(x^25)) \\ _Colin Barker_, Jun 25 2020
%Y A335749 Cf. A335312.
%K A335749 nonn,easy
%O A335749 0,2
%A A335749 _Peter Luschny_, Jun 24 2020