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 A011548 #25 Jul 08 2025 07:47:58
%S A011548 1,14,141,1414,14142,141421,1414214,14142136,141421356,1414213562,
%T A011548 14142135624,141421356237,1414213562373,14142135623731,
%U A011548 141421356237310,1414213562373095,14142135623730950,141421356237309505,1414213562373095049,14142135623730950488,141421356237309504880
%N A011548 Decimal expansion of sqrt(2) rounded to n places.
%D A011548 W. Rudin, Principles of Mathematical Analysis, 3rd ed., McGraw-Hill, 1976.
%H A011548 G. C. Greubel, <a href="/A011548/b011548.txt">Table of n, a(n) for n = 0..995</a> (terms 0..200 from Vincenzo Librandi)
%t A011548 Round[Table[N[Sqrt[2], k] 10^(k - 1), {k, 20}]] (* _Vincenzo Librandi_, Aug 17 2013 *)
%t A011548 Module[{nn=20,s},s=RealDigits[Sqrt[2],10,nn+1][[1]];Table[Round[ FromDigits[ Take[ s,n+1]]/10],{n,nn}]] (* _Harvey P. Dale_, Apr 04 2019 *)
%o A011548 (Python)
%o A011548 from math import isqrt
%o A011548 def A011548(n): return (m:=isqrt(k:=10**(n<<1)<<1))+int((k-m*(m+1)<<2)>=1) # _Chai Wah Wu_, Jul 29 2022
%Y A011548 Cf. A002193, A011547, A011552, A011544, A011546.
%K A011548 nonn,base,easy
%O A011548 0,2
%A A011548 _N. J. A. Sloane_