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 A011547 #17 Jul 08 2025 02:26:40
%S A011547 1,14,141,1414,14142,141421,1414213,14142135,141421356,1414213562,
%T A011547 14142135623,141421356237,1414213562373,14142135623730,
%U A011547 141421356237309,1414213562373095,14142135623730950
%N A011547 Decimal expansion of sqrt(2) truncated to n places.
%D A011547 W. Rudin, Principles of Mathematical Analysis, 3rd ed., McGraw-Hill, 1976.
%H A011547 Vincenzo Librandi, <a href="/A011547/b011547.txt">Table of n, a(n) for n = 0..200</a>
%t A011547 With[{sqrt2=N[Sqrt[2],30]},Table[IntegerPart[sqrt2 10^n],{n,0,20}]] (* _Harvey P. Dale_, Sep 22 2011 *)
%t A011547 IntegerPart[Table[N[Sqrt[2], k] 10^(k - 1), {k, 20}]] (* _Vincenzo Librandi_, Aug 16 2013 *)
%Y A011547 Cf. A011548.
%K A011547 nonn,base
%O A011547 0,2
%A A011547 _N. J. A. Sloane_