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 A006059 Number of connected labeled T_0-T_4-topologies with n points. (Formerly M1948) 9
 1, 1, 2, 9, 76, 1095, 25386, 910161, 49038872, 3885510411, 445110425110, 72721717736613, 16755380125270788, 5393244363726095487, 2405910197342218830914, 1477264863856923105482745, 1241074736327051013648799024, 1419169006353332682835352361843 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 REFERENCES N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Herman Jamke, Table of n, a(n) for n = 0..19 M. Erné, Struktur- und Anzahlformeln für Topologien auf Endlichen Mengen, Manuscripta Math., 11 (1974), 221-259. M. Erné, Struktur- und Anzahlformeln für Topologien auf Endlichen Mengen, Manuscripta Math., 11 (1974), 221-259. (Annotated scanned copy) FORMULA a(n) = n*A001035(n-1) for n>=1. - Herman Jamke (hermanjamke(AT)fastmail.fm), Mar 02 2008 CROSSREFS Sequences in the Erné (1974) paper: A000798, A001035, A006056, A006057, A001929, A001927, A006058, A006059, A000110. Sequence in context: A132621 A108992 A058164 * A277406 A182947 A006041 Adjacent sequences:  A006056 A006057 A006058 * A006060 A006061 A006062 KEYWORD nonn,nice AUTHOR EXTENSIONS More terms from Detlef Pauly (dettodet(AT)yahoo.de), Dec 27 2001 STATUS approved

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Last modified December 10 00:30 EST 2018. Contains 318032 sequences. (Running on oeis4.)