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

 

Logo

The submissions stack has been unacceptably high for several months now. Please voluntarily restrict your submissions and please help with the editing. (We don't want to have to impose further limits.)

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A147961 ((6+sqrt3)^n+(6-sqrt3)^n/2 1
1, 6, 39, 270, 1953, 14526, 109863, 838998, 6442497, 49623030, 382873959, 2956927518, 22848289569, 176600866734, 1365216845031, 10554773538150, 81605126571777, 630953992102374, 4878478728359847, 37720263000939822 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..19.

FORMULA

a(n)=12*a(n-1)-33*a(n-2), n>1 ; a(0)=1, a(1)=6 . G.f.: (1-6x)/(1-12x+33x^2). a(n)=(Sum_{k, 0<=k<=n} A098158(n,k)*6^(2k)*3^(n-k))/6^n. [From Philippe Deléham, Nov 19 2008]

EXAMPLE

a(3)=270

PROG

(MAGMA) Z<x>:= PolynomialRing(Integers()); N<r3>:=NumberField(x^2-3); S:=[ ((6+r3)^n+(6-r3)^n)/2: n in [0..19] ]; [ Integers()!S[j]: j in [1..#S] ]; [From Klaus Brockhaus, Nov 19 2008]

CROSSREFS

Sequence in context: A006256 A052392 A199491 * A068765 A006633 A153392

Adjacent sequences:  A147958 A147959 A147960 * A147962 A147963 A147964

KEYWORD

nonn

AUTHOR

Al Hakanson (hawkuu(AT)gmail.com), Nov 17 2008

EXTENSIONS

Extended beyond a(6) by Klaus Brockhaus, Nov 19 2008

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified August 28 05:09 EDT 2015. Contains 261118 sequences.