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 A029848 #22 Aug 08 2025 09:10:37
%S A029848 3,6,22,105,566,3256,19489,119713,748342,4735446,30229772,194242153,
%T A029848 1254381857,8132826045,52900345681,345022543105,2255449994038,
%U A029848 14773402692946,96935423713906,637019314585501,4191982352334316,27619973660237476,182185272080724121,1202945209263916561
%N A029848 a(n) = 1 + C(2*n,n) + C(3*n,n).
%H A029848 Seiichi Manyama, <a href="/A029848/b029848.txt">Table of n, a(n) for n = 0..1000</a>
%F A029848 G.f.: 1/(1-x)+1/sqrt(1-4*x)+cos(arcsin((3^(3/2)*sqrt(x))/2)/3)/sqrt(1-(27*x)/4). - _Vladimir Kruchinin_, Aug 07 2025
%p A029848 a:=n->1+binomial(2*n,n)+binomial(3*n,n): seq(a(n),n=0..20); # _Muniru A Asiru_, Aug 12 2018
%t A029848 Table[1+Binomial[2n,n]+Binomial[3n,n],{n,0,30}] (* _Harvey P. Dale_, Jan 09 2019 *)
%o A029848 (PARI) a(n) = 1 + binomial(2*n, n) + binomial(3*n, n); \\ _Michel Marcus_, Aug 12 2018
%o A029848 (GAP) List([0..20],n->1+Binomial(2*n,n)+Binomial(3*n,n)); # _Muniru A Asiru_, Aug 12 2018
%Y A029848 Cf. A000984, A096131.
%K A029848 nonn
%O A029848 0,1
%A A029848 _N. J. A. Sloane_