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 A053481 #7 Jan 19 2017 02:33:09
%S A053481 2,11,76,654,6816,83880,1193760,19318320,350622720,7056927360,
%T A053481 156031142400,3760042809600,98093779660800,2754553785984000,
%U A053481 82841868639129600,2656672553703168000,90498598469959680000,3263440333591646208000
%N A053481 First differences of A029767.
%H A053481 G. C. Greubel, <a href="/A053481/b053481.txt">Table of n, a(n) for n = 0..400</a>
%F A053481 a(n) = (n+1)!*(2^(n+2) -1) - n!*(2^(n+1) -1) for n>=0. - _G. C. Greubel_, Jan 19 2017
%t A053481 a[n_] := (n - 1)! * (2^n - 1); Table[a[n+2] - a[n+1], {n,0,25}] (* _G. C. Greubel_, Jan 19 2017 *)
%o A053481 (PARI) for(n=0,25, print1(( (n+1)!*(2^(n+2) -1) - n!*(2^(n+1) -1)), ", ")) \\ _G. C. Greubel_, Jan 19 2017
%K A053481 nonn
%O A053481 0,1
%A A053481 _N. J. A. Sloane_, Jan 15 2000