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 A330161 #9 Dec 08 2019 12:31:52
%S A330161 7,8,4,3,43,88,67,148,267,760,232,1320,163,1848,45208,124195,169603,
%T A330161 85507,121972,261627,424708,656755,35230603,80149435,154962808,
%U A330161 289615747
%N A330161 Fundamental discriminant D < 0 with the least absolute value such that the smallest prime p such that Kronecker(D,p) = 1 is p = prime(n), negated.
%C A330161 If a(n) < (Pi*prime(n)/2)^2 (this occurs for n <= 14), then the ideal class group of Q[sqrt(-d)] necessarily has exponent <= 2. (The exponent of a group G is the smallest e > 0 such that x^e = I for all x in G, where I is the group identity.) See A330221.
%C A330161 It seems that lim_{n->oo} n^t/a(n) = 0 for all t > 0.
%C A330161 The exponent of the ideal class group of Q[sqrt(-a(n))]: 1, 1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 26, 16, 36, 22, 38, 24, 16, 36, 104, 388, 104, 288, ...
%e A330161 D = -1848 is the fundamental discriminant D < 0 with the least absolute value such that Kronecker(D,p) <= 0 for p = 2, 3, 5, 7, ..., 41 and Kronecker(D,43) = +1, so a(14) = 1848.
%o A330161 (PARI) b(D)=forprime(p=2, oo, if(kronecker(D, p)>0, return(p)))
%o A330161 a(n)=my(p=prime(n)); for(D=3, oo, if(isfundamental(-D) && b(-D)==p, return(D)))
%Y A330161 Cf. A306538, A330221.
%K A330161 nonn,more
%O A330161 1,1
%A A330161 _Jianing Song_, Dec 03 2019