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 A223166 #15 Feb 16 2025 08:33:19
%S A223166 4,28,175,1244,9628,78625,664916,5762207,50849233,455055612,
%T A223166 4118066398,37607950279,346065645808,3204942065690,29844571475285,
%U A223166 279238344248555,2623557165610820,24739954309690413,234057667376222380,2220819602783663481
%N A223166 Integer nearest to Li(10^n) - Li(3), where Li(x) = integral(0..x, dt/log(t)).
%H A223166 Vladimir Pletser, <a href="/A223166/b223166.txt">Table of n, a(n) for n = 1..1000</a>
%H A223166 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PrimeCountingFunction.html">Prime Counting Function</a>
%H A223166 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LogarithmicIntegral.html">Logarithmic Integral</a>
%F A223166 a(n) = round(Li( 10^n)-Li(3)).
%p A223166 seq(round(evalf(integrate(1/log(t), t=3..10^n))), n=1..1000);
%t A223166 Table[Round[LogIntegral[10^n]-LogIntegral[3]],{n,30}] (* _Harvey P. Dale_, Aug 24 2022 *)
%Y A223166 Cf. A057754, A006880, A190802.
%K A223166 nonn
%O A223166 1,1
%A A223166 _Vladimir Pletser_, Mar 16 2013