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 A091102 #16 Feb 16 2025 08:32:52
%S A091102 3,14,87,623,4818,39263,332406,2881124,25425200,227528084
%N A091102 Number of first half-quadrant Gaussian primes whose norm is less than 10^n.
%H A091102 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GaussianPrime.html">Gaussian Prime</a>
%H A091102 <a href="/index/Ga#gaussians">Index entries for Gaussian integers and primes</a>
%F A091102 a(2n) = A091098(2n) + A091099(n) + 1
%t A091102 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, x}]; cnt, {n, 6}]
%Y A091102 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.
%K A091102 nonn,more
%O A091102 1,1
%A A091102 _T. D. Noe_, Dec 19 2003
%E A091102 a(10) calculated from the data at A091098 and A091099 by _Amiram Eldar_, Feb 28 2020