Given any prime number l which is a primitive root modulo 529 (=232), we shall prove that the l-class group of the Z23-extension over the rational field is trivial.
"The ideal class group of the Z23-extension over the rational field." Proc. Japan Acad. Ser. A Math. Sci. 85 (10) 155 - 159, December 2009. https://doi.org/10.3792/pjaa.85.155