login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

Table of n, a(n) for n=2..21.

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified June 27 07:55 EDT 2017. Contains 288777 sequences.