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 A249945 #20 Aug 29 2022 20:42:30
%S A249945 2,4,11,33,105,363,1449,7227,46881,382563,3687849,40093947,479533041,
%T A249945 6228615123,87183074169,1307688716907,20922832934721,355687557236163,
%U A249945 6402374093148489,121645101571093467,2432902011663424401,51090942182169793203,1124000727808988739609
%N A249945 a(n) = n! + 3^n.
%F A249945 a(n) = n! + 3^n.
%F A249945 a(n) = A000142(n) + A000244(n).
%F A249945 E.g.f.: 1/(1-x) + exp(3*x). - _Alois P. Heinz_, Aug 29 2022
%p A249945 A249945:=n->3^n+n!: seq(A249945(n), n=0..25); # _Wesley Ivan Hurt_, Nov 14 2014
%t A249945 Table[3^n + n!, {n, 20}] (* _Alonso del Arte_, Nov 09 2014 *)
%o A249945 (PARI) vector(10,n,3^n + n!) \\ _Derek Orr_, Nov 14 2014
%o A249945 (Magma) [3^n+Factorial(n) : n in [0..25]]; // _Wesley Ivan Hurt_, Nov 14 2014
%Y A249945 Cf. A000142, A000244, A007611.
%K A249945 nonn,easy
%O A249945 0,1
%A A249945 _Max Alweiss_, Nov 08 2014