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 A295473 #14 Sep 08 2022 08:46:20
%S A295473 0,9,18,54,216,1080,6480,45360,362880,3265920,32659200,359251200,
%T A295473 4311014400,56043187200,784604620800,11769069312000,188305108992000,
%U A295473 3201186852864000,57621363351552000,1094805903679488000,21896118073589760000,459818479545384960000
%N A295473 a(0) = 0; for n>0, a(n) = 9*n!.
%H A295473 Vincenzo Librandi, <a href="/A295473/b295473.txt">Table of n, a(n) for n = 0..300</a>
%F A295473 E.g.f.: 9*x/(1-x).
%F A295473 a(n) = n*a(n-1) = 9*A000142(n) for n>0.
%t A295473 Join[{0}, 9 Range[25]!]
%o A295473 (Magma) [n eq 0 select 0 else 9*Factorial(n): n in [0..25]];
%o A295473 (PARI) a(n) = (n > 0)*9*n! \\ _Felix Fröhlich_, Feb 15 2018
%Y A295473 Cf. A000142.
%Y A295473 Cf. similar sequences listed in A298881.
%K A295473 nonn,easy
%O A295473 0,2
%A A295473 _Vincenzo Librandi_, Feb 14 2018