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 A055550 Number of Poulet numbers (or pseudoprimes to base 2, A001567) less than 10^n. 4
 0, 0, 3, 22, 78, 245, 750, 2057, 5597, 14884, 38975, 101629, 264239, 687007, 1801533, 4744920, 12604009, 33763684, 91210364 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 REFERENCES J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 245, pp 68, Ellipses, Paris 2008. - Lekraj Beedassy, Jul 20 2008 LINKS Jan Feitsma and William Galway, Tables of pseudoprimes and related data Eric Weisstein's World of Mathematics, Poulet Number Eric Weisstein's World of Mathematics, Pseudoprime MATHEMATICA Table[Count[Select[Range[2, 10^6], ! PrimeQ[#] && PowerMod[2, # - 1, #] == 1 &], x_ /; x < 10^n], {n, 6}]  (* Robert Price, Jun 09 2019 *) CROSSREFS Cf. A001567, A055552. Sequence in context: A005288 A143166 A268792 * A075204 A106150 A135836 Adjacent sequences:  A055547 A055548 A055549 * A055551 A055552 A055553 KEYWORD nonn,more AUTHOR EXTENSIONS a(14) and a(15) computed by William F. Galway and communicated by Arthur Livingstone (arthur.livingstone(AT)gmail.com), Apr 10 2007 Edited by N. J. A. Sloane, Feb 01 2009 at the suggestion of Charles R Greathouse IV a(14)-a(15) recomputed (were missing) and a(16)-a(19) added by Charles R Greathouse IV, Jan 28 2011, based on the calculations of Jan Feitsma STATUS approved

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Last modified May 27 21:52 EDT 2020. Contains 334671 sequences. (Running on oeis4.)