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 A328820 #10 Dec 01 2019 03:01:01
%S A328820 0,2,0,0,0,4,7,4,0,2,6,1,5,6,9,0,1,6,8,1,5,4,8,9,0,0,1,5,1,2,7,8,5,9,
%T A328820 0,0,7,4,9,5,1,7,4,2,2,3,6,2,0,0,4,1,1,4,1,3,8,7,1,9,2,0,2,0,2,0,3,2,
%U A328820 6,6,1,2,0,3,2,7,9,7,1,2,0,3,4,1,5,6,3,8,9,8,3,6,6,3,7,9,8,4,8,0
%N A328820 Fourth digit after decimal point of square root of n.
%H A328820 Maxim Skorohodov, <a href="/A328820/b328820.txt">Table of n, a(n) for n = 1..10000</a>
%F A328820 a(n) = A010879(A000196(100000000*n)).
%e A328820 sqrt(5) = 2.23606798..., so a(5) = 0.
%o A328820 (C++) int a(int n) { return int(10000 * sqrt(n)) % 10; }
%Y A328820 Cf. A111862, A023961.
%K A328820 nonn,easy,base
%O A328820 1,2
%A A328820 _Maxim Skorohodov_, Oct 28 2019