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 A091099 #11 Feb 16 2025 08:32:52
%S A091099 2,13,87,619,4808,39322,332398,2880950,25424042,227529235,2059034532,
%T A091099 18803987677,173032827655,1602470967129,14922285687184,
%U A091099 139619172246129,1311778581969146,12369977145161275,117028833678543917,1110409801410336132
%N A091099 Number of primes of the form 4k+3 less than 10^n.
%H A091099 Marc Deleglise, Pierre Dusart, and Xavier-Francois Roblot, <a href="http://www.ams.org/journals/mcom/2004-73-247/S0025-5718-04-01649-7/">Counting primes in residue classes</a>, Math. Comp. 73 (2004), no. 247, 1565-1575
%H A091099 Daniel Pareja, <a href="http://www.math.ubc.ca/~gerg/teaching/613-Winter2011/PrimeNumberRaces.pdf">Prime Number Races</a>
%H A091099 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ModularPrimeCountingFunction.html">Modular Prime Counting Function</a>
%t A091099 cnt=0; k=0; Table[lim=10^n; While[4k+3<lim, If[ PrimeQ[4k+3], cnt++ ]; k++ ]; cnt, {n, 6}]
%Y A091099 Cf. A091098 (number of primes of the form 4k+1 less than 10^n).
%K A091099 nonn
%O A091099 1,1
%A A091099 _T. D. Noe_, Dec 19 2003
%E A091099 a(10)-a(16) from _Robert G. Wilson v_, Dec 22 2003
%E A091099 a(17)-a(20) from _Marc Deleglise_, Jun 28 2007