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 A091101 #16 Feb 16 2025 08:32:52
%S A091101 5,27,173,1245,9635,78525,664811,5762247,50850399,455056167
%N A091101 Number of first-quadrant Gaussian primes whose norm is less than 10^n.
%H A091101 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GaussianPrime.html">Gaussian Prime</a>
%H A091101 <a href="/index/Ga#gaussians">Index entries for Gaussian integers and primes</a>
%F A091101 a(2n) = 2*A091098(2n) + 2*A091099(n) + 1.
%t A091101 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, 0, lim1}, {y, 0, lim1}]; cnt, {n, 6}]
%Y A091101 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), A091100, A091102.
%K A091101 nonn,more
%O A091101 1,1
%A A091101 _T. D. Noe_, Dec 19 2003
%E A091101 a(10) calculated from the data at A091098 and A091099 by _Amiram Eldar_, Feb 28 2020