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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A279122 Denominators of coefficients in expansion of 3/(1 + 2 cos(sqrt(x))). 3
1, 3, 12, 360, 181440, 1814400, 34214400, 130767436800, 10461394944000, 457312407552000, 3649353012264960000, 562000363888803840000, 3409057152380436480000, 5444434725209176080384000000, 152444172305856930250752000000, 18946632843727932759736320000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Clark Kimberling, Table of n, a(n) for n = 0..999

EXAMPLE

1/1 + (1/3)x + (1/12)x^2 + (7/360)x^3 + ... ; 1/1, 1/2, 1/12, 7/360, 809/181440, ... = A279122/A279121.

MATHEMATICA

Denominator[CoefficientList[Series[3/(1 + 2 Cos[Sqrt[x]]), {x, 0, 30}], x]]

CROSSREFS

Cf. A279120, A279122.

Sequence in context: A300532 A249940 A132515 * A246957 A216897 A262541

Adjacent sequences:  A279119 A279120 A279121 * A279123 A279124 A279125

KEYWORD

nonn,easy,frac

AUTHOR

Clark Kimberling, Dec 07 2016

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 18 17:05 EDT 2019. Contains 324214 sequences. (Running on oeis4.)