Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #8 Oct 13 2017 05:48:45
%S 16,8,8,8,16,16,8,32,16,16,16,8,16,8,64,8,8,8,8,128,16,8,8,32
%N 2-class number of Q(sqrt(-21p)) as p runs through primes in A102271.
%H H. Cohn and J. C. Lagarias, <a href="http://doi.org/10.1090/S0025-5718-1983-0717716-8">On the existence of fields governing the 2-invariants of the classgroup of Q(sqrt{dp}) as p varies</a>, Math. Comp. 41 (1983), 711-730.
%Y Cf. A102269, A102270, A102271, A102273, A102274, A102275.
%K nonn,more
%O 1,1
%A _N. J. A. Sloane_, Feb 19 2005