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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A182568 Floor(n/4)*(2*n-4*(1+floor(n/4))). 0
0, 0, 0, 0, 0, 2, 4, 6, 8, 12, 16, 20, 24, 30, 36, 42, 48, 56, 64, 72, 80, 90, 100, 110, 120, 132, 144, 156, 168, 182, 196, 210, 224, 240, 256, 272, 288, 306, 324, 342, 360, 380, 400, 420, 440, 462, 484, 506, 528, 552, 576, 600, 624, 650, 676, 702, 728, 756, 784, 812, 840, 870, 900, 930, 960, 992, 1024, 1056, 1088, 1122, 1156, 1190, 1224, 1260, 1296, 1332, 1368 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

REFERENCES

Ho, Pak Tung. The toroidal crossing number of K_{4,n}. Discrete Math. 309 (2009), no. 10, 3238--3248. MR2526742(2010i:05088)

LINKS

Table of n, a(n) for n=0..76.

Index entries for linear recurrences with constant coefficients, signature (2,-1,0,1,-2,1).

FORMULA

G.f. -2*x^5 / ( (1+x)*(x^2+1)*(x-1)^3 ). a(n) = 2*A001972(n-5) = 2*A130519(n-1). - R. J. Mathar, Jun 28 2012

CROSSREFS

Sequence in context: A050622 A082662 A246663 * A064522 A036912 A097921

Adjacent sequences:  A182565 A182566 A182567 * A182569 A182570 A182571

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, May 05 2012

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 April 24 04:19 EDT 2018. Contains 302984 sequences. (Running on oeis4.)