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 A048345 #30 Feb 16 2025 08:32:39
%S A048345 0,10,320,100,3200,1000,32000,10000,320000,100000,3200000,1000000,
%T A048345 32000000,10000000,320000000,100000000,3200000000,1000000000,
%U A048345 32000000000,10000000000,320000000000,100000000000
%N A048345 a(n)^2 is the smallest square containing exactly n 0's.
%H A048345 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SquareNumber.html">Square Number</a>
%H A048345 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,10).
%F A048345 From _Ralf Stephan_, Jul 18 2013: (Start)
%F A048345 a(n) = 10*a(n-2); a(0)=0, a(1)=10, a(2)=320.
%F A048345 G.f.: (10*x + 320*x^2)/(1-10*x^2). (End)
%t A048345 LinearRecurrence[{0,10},{0,10,320},30] (* _Harvey P. Dale_, Feb 10 2022 *)
%o A048345 (Magma) a:=[0,10,320]; [n le 3 select a[n] else 10*Self(n-2):n in [1..25]]; // _Marius A. Burtea_, Oct 11 2019
%Y A048345 Cf. A000290, A036507.
%K A048345 nonn,base,easy
%O A048345 1,2
%A A048345 _Patrick De Geest_, Mar 15 1999
%E A048345 More terms from _Lior Manor_, Jul 02 2001
%E A048345 a(20) corrected by _Georg Fischer_, Dec 07 2019