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 A230869 #24 Feb 16 2021 02:08:25
%S A230869 163,191,229,257,277,313,349,397,401,457,491,521,547,577,607,631,641,
%T A230869 709,733,761,821,827,829,853,857,877,937,941,953,977,1009,1063,1069,
%U A230869 1093,1129,1153,1229,1231,1297,1373,1381,1399,1429,1459,1489,1567,1601,1697,1699,1777,1789,1831,1861,1873,1879,1889,1901,1951
%N A230869 Primes p such that the class number h-tilde_p^{+} of the real cyclotomic field Q(zeta_p + zeta_p^(-1)) is greater than 1.
%C A230869 Taken from the "Main Table" of Schoof.
%C A230869 There is a very slight chance that some primes are missing. In the unlikely event that the number that Schoof calls h-tilde_p is 1, while the actual class number h_p is actually not equal to 1, the prime p would be missing (see the Schoof and Miller articles for details).
%H A230869 John C. Miller, <a href="https://arxiv.org/abs/1405.1094">Class numbers of totally real fields and applications to the Weber class number problem</a>, arXiv:1405.1094 [math.NT], 2014.
%H A230869 John C. Miller, <a href="https://arxiv.org/abs/1407.2373">Real cyclotomic fields of prime conductor and their class numbers</a>, arXiv:1407.2373 [math.NT], 2014.
%H A230869 Rene Schoof, <a href="https://doi.org/10.1090/S0025-5718-02-01432-1">Class numbers of real cyclotomic fields of prime conductor</a>, Math. Comp., 72 (2002), 913-937.
%Y A230869 Cf. A230870 (for the actual class numbers).
%Y A230869 See also A000927, A055513, A035113, A035114, A035115.
%K A230869 nonn
%O A230869 1,1
%A A230869 _N. J. A. Sloane_, Nov 06 2013