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 A380782 #10 Feb 11 2025 14:33:28
%S A380782 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,3,1,1,1,1,1,1,1,1,1,1,1,1,
%T A380782 1,1,1,1,1,1,1,1,1,1,1,1,1,3,1,3,1,1,1,1,3,1,1,1,1,1,1,1,1,1,1,1,1,1,
%U A380782 1,1,1,3,1,1,1,1,1,1,5,1,1,1,1,1,5,3,1
%N A380782 Class number of real quadratic field Q(sqrt(prime(n))).
%C A380782 A278837 contains all primes p where the class number of Q(sqrt(p)) is larger than 1.
%e A380782 For n = 22, a(22) = 3 since the class number of Q(sqrt(79)) is 3 where 79 is the 22nd prime.
%t A380782 Table[NumberFieldClassNumber[Sqrt[Prime[i]]], {i, 87}]
%Y A380782 Cf. A003172, A076498, A278837.
%K A380782 nonn
%O A380782 1,22
%A A380782 _Steven Lu_, Feb 02 2025