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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A156865 729000n - 612180. 4
116820, 845820, 1574820, 2303820, 3032820, 3761820, 4490820, 5219820, 5948820, 6677820, 7406820, 8135820, 8864820, 9593820, 10322820, 11051820, 11780820, 12509820, 13238820, 13967820, 14696820, 15425820, 16154820, 16883820 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The identity(32805000*n^2-55096200*n+23133601)^2-(2025*n^2-649*n+52)*(729000*n-612180)^2=1 can be written as A157078(n)^2-A156853(n)*a(n)^2=1.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

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

FORMULA

a(n) = 2*a(n-1) - a(n-2).

G.f. 180*x*(649+3401*x)/(x-1)^2.

MATHEMATICA

LinearRecurrence[{2, -1}, {116820, 845820}, 40]

PROG

(MAGMA) I:=[116820, 845820]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..40]];

(PARI) a(n)=729000*n-612180 \\ Charles R Greathouse IV, Dec 23 2011

CROSSREFS

Cf. A156853, A157078.

Sequence in context: A252886 A046407 A156417 * A233681 A246557 A289911

Adjacent sequences:  A156862 A156863 A156864 * A156866 A156867 A156868

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Feb 17 2009

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 17 22:17 EDT 2019. Contains 324200 sequences. (Running on oeis4.)