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 A173038 Numbers of the form (1/4)*(n^2 - 5 n + 2)*(n - 2)! + 1 0
 0, 0, 0, 4, 49, 481, 4681, 47881, 524161, 6168961, 78019201, 1057795201, 15328051201, 236626790401, 3879433958401, 67345229952001, 1234444603392001, 23831057682432001, 483379214782464001, 10279010984546304001 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,4 COMMENTS Genera of curves B whose function field K(B) is Galois closure [Galois closed, perhaps? - N. J. A. Sloane, Feb 08 2010]. a(n) is also the cyclomatic number of the (n-2)-transposition graph. - Eric W. Weisstein, Apr 03 2017 REFERENCES Nils Bruin and Noam D. Elkies, Trinomials ax^7+bx+c and ax^8+bx+c with Galois Groups of Order 168 and 8*168, in Claus Fieker, David R. Kohel (Editors): Algorithmic Number Theory, 5th International Symposium, ANTS-V, Lecture Notes in Computer Science 2369 Springer 2002, pp. 172 - 188. LINKS Eric Weisstein's World of Mathematics, Cyclomatic Number Eric Weisstein's World of Mathematics, Transposition Graph MATHEMATICA Table[(1/4) (n^2 - 5 n + 2) (n - 2)! + 1, {n, 2, 30}] CROSSREFS Sequence in context: A045787 A067474 A053769 * A198971 A273230 A199028 Adjacent sequences:  A173035 A173036 A173037 * A173039 A173040 A173041 KEYWORD nonn AUTHOR Artur Jasinski, Feb 08 2010 STATUS approved

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