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 A355877 #12 Jul 20 2022 08:49:12 %S A355877 5,229,1093,2029,7573,12589,8101,13693,54541,18229,75629,91813,59053, %T A355877 65029,72901,146077,127453,199813,169909,209581,439573,189229,197341, %U A355877 324901,378229,596293,430861,352837,712981,1137229,700573,245029,574261,770533,860701,1432813,1821877,1092829 %N A355877 Smallest prime p == 5 (mod 8) such that Q(sqrt(p)) has class number 2n+1. %H A355877 Wikipedia, <a href="http://en.wikipedia.org/wiki/Class_number_(number_theory)#Class_numbers_of_quadratic_fields">Class numbers of quadratic fields</a> %H A355877 <a href="/index/Qua#quadfield">Index entries for sequences related to quadratic fields</a> %e A355877 p = 229 is the smallest prime congruent to 5 modulo 8 such that Q(sqrt(p)) has class number 3, so a(1) = 229. %o A355877 (PARI) a(n) = forprime(p=2, oo, if(p%8==5 && qfbclassno(p)==2*n+1, return(p))) %Y A355877 Cf. A355878. %Y A355877 Similar sequences: A355876 (p == 1 (mod 8)), A002148 (p == 3 (mod 8)), A002146 (p == 7 (mod 8)). %K A355877 nonn %O A355877 0,1 %A A355877 _Jianing Song_, Jul 20 2022