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 A135321 #12 Sep 08 2022 08:45:32
%S A135321 1,90,656100,387420489000,18530201888518410000,
%T A135321 71789798769185258877024900000,
%U A135321 22528399544939174411840147874772641000000
%N A135321 a(n) = 10^n * 9^(n^2).
%C A135321 Hankel transform of A131521.
%H A135321 Vincenzo Librandi, <a href="/A135321/b135321.txt">Table of n, a(n) for n = 0..30</a>
%F A135321 a(n) = 10^n * 9^(n^2) = A011557(n) * A060761(n).
%t A135321 Table[10^n * 9^(n^2), {n,0,10}] (* _G. C. Greubel_, Oct 09 2016 *)
%o A135321 (Magma) [10^n*9^(n^2): n in [0..10]]; // _Vincenzo Librandi_, May 31 2011
%o A135321 (PARI) a(n)=10^n*9^(n^2) \\ _Charles R Greathouse IV_, Oct 09 2016
%Y A135321 Cf. A011557, A060761, A131521.
%K A135321 nonn,easy
%O A135321 0,2
%A A135321 _Philippe Deléham_, Dec 06 2007