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 A089290 #18 Feb 07 2022 02:27:09
%S A089290 3,4,8,9,5,5,7,4,9,3,8,7,7,5,5,8,1,4,3,7,4,6,3,7,1,4,3,6,8,6,6,2,2,4,
%T A089290 3,2,6,7,7,5,6,3,3,6,6,6,9,7,3,4,4,9,8,1,1,1,8,3,3,7,2,7,7,9,3,3,1,9,
%U A089290 1,7,2,2,8,1,9,6,8,8,7,7,7,6,3,5,4,4,7
%N A089290 Digital root of floor(Pi*10^n), Pi=3.14....
%H A089290 Nathaniel Johnston, <a href="/A089290/b089290.txt">Table of n, a(n) for n = 0..10000</a>
%F A089290 a(n) = A010888(A011545(n)).
%e A089290 n=10: floor(Pi*10^n) = 31415926535 -> 3 + 1 + 4 + 1 + 5 + 9 + 2 + 6 + 5 + 3 + 5 = 44 -> 4 + 4 = 8, so a(10)=8.
%p A089290 A089290 := proc(n) Digits:=n+20: return ((floor(Pi*10^n)-1) mod 9) + 1: end: seq(A089290(n),n=0..100); # _Nathaniel Johnston_, May 04 2011
%t A089290 Table[ Mod[ Floor[ Pi*10^n], 9], {n, 0, 104}] /. 0 -> 9 (* _Robert G. Wilson v_, Oct 31 2003 *)
%Y A089290 Cf. A046974, A000796.
%K A089290 nonn,easy,base
%O A089290 0,1
%A A089290 _Reinhard Zumkeller_, Oct 30 2003
%E A089290 More terms from _Ray Chandler_ and _Robert G. Wilson v_, Oct 31 2003