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 A091100 #23 Feb 16 2025 08:32:52
%S A091100 16,100,668,4928,38404,313752,2658344,23046512,203394764,1820205436,
%T A091100 16472216912,150431552012,1384262129028,12819767598972,
%U A091100 119378281788240,1116953361826164
%N A091100 Number of Gaussian primes whose norm is less than 10^n.
%H A091100 Marc Deléglise, Pierre Dusart, and Xavier-Francois Roblot, <a href="http://dx.doi.org/10.1090/S0025-5718-04-01649-7">Counting primes in residue classes</a>, Math. Comp. 73 (2004), no. 247, 1565-1575
%H A091100 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GaussianPrime.html">Gaussian Prime</a>
%H A091100 <a href="/index/Ga#gaussians">Index entries for Gaussian integers and primes</a>
%F A091100 a(2n) = 8*A091098(2n) + 4*A091099(n) + 4.
%F A091100 a(n) ~ 4 Li(10^n) ~ k/n * 10^n, where k = 4/log(10) = 1.737.... - _Charles R Greathouse IV_, Oct 24 2012
%t A091100 Table[lim2=10^n; lim1=Floor[Sqrt[lim2]]; cnt=0; Do[If[x^2+y^2<lim2&&PrimeQ[x+I y, GaussianIntegers->True], cnt++ ], {x, -lim1, lim1}, {y, -lim1, lim1}]; cnt, {n, 6}]
%Y A091100 Cf. A091098 (number of primes of the form 4k+1 less than 10^n), A091099 (number of primes of the form 4k+3 less than 10^n), A091101, A091102.
%Y A091100 Cf. A091134 (number of Gaussian primes whose modulus is less than 10^n).
%Y A091100 Cf. A017934, A295996.
%K A091100 nonn
%O A091100 1,1
%A A091100 _T. D. Noe_, Dec 19 2003
%E A091100 a(10)-a(16) from _Seiichi Manyama_ using the data in A091098, Dec 03 2017