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 A055513 Class number h = h- * h+ of cyclotomic field Q( exp(2 Pi / prime(n)) ). 7
 1, 1, 1, 1, 1, 1, 1, 3, 8, 9, 37, 121, 211, 695, 4889, 41241, 76301, 853513, 3882809, 11957417, 100146415, 838216959, 13379363737, 411322824001, 3547404378125, 9069094643165, 63434933542623, 161784800122409, 1612072001362952, 2604529186263992195, 28496379729272136525, 646901570175200968153, 1753848916484925681747, 687887859687174720123201, 2333546653547742584439257, 56234327700401832767069245, 10834138978768308207500526544 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,8 COMMENTS Washington gives a very extensive table (but beware errors!). REFERENCES Z. I. Borevich and I. R. Shafarevich, Number Theory. Academic Press, NY, 1966, p. 429. L. C. Washington, Introduction to Cyclotomic Fields, Springer, pp. 353-360. LINKS Hisanori Mishima, Factorizations of Cyclotomic Numbers M. Newman, A table of the first factor for prime cyclotomic fields, Math. Comp., 24 (1970), 215-219. M. A. Shokrollahi, Tables EXAMPLE For n = 9, prime(9) = 23, a(9) = 3. For n = 38, prime(38) = 163, a(38) = 4*2708534744692077051875131636 = 10834138978768308207500526544. CROSSREFS For the relative class number h-, see A000927, which agrees for the first 36 terms, assuming the Generalized Riemann Hypothesis. Cf. A035115, A055514, A061653. Sequence in context: A101720 A093439 A000927 * A038226 A095866 A067569 Adjacent sequences:  A055510 A055511 A055512 * A055514 A055515 A055516 KEYWORD nonn,nice AUTHOR N. J. A. Sloane, Jun 16 2001 EXTENSIONS Washington incorrectly gives a(17) = 41421, a(25) = 411322842001. Edited by Max Alekseyev, Oct 25 2012 STATUS approved

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Last modified April 9 12:29 EDT 2020. Contains 333350 sequences. (Running on oeis4.)