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

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A172043 5n^2 - n + 1. 2
1, 5, 19, 43, 77, 121, 175, 239, 313, 397, 491, 595, 709, 833, 967, 1111, 1265, 1429, 1603, 1787, 1981, 2185, 2399, 2623, 2857, 3101, 3355, 3619, 3893, 4177, 4471, 4775, 5089, 5413, 5747, 6091, 6445, 6809, 7183, 7567, 7961, 8365, 8779, 9203, 9637, 10081 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

G.f.: (1+2*x+7*x^2)/(1-x)^3. - Vincenzo Librandi, Jul 06 2012

a(n) = 3*a(n-1) -3*a(n-2) +a(n-3). - Vincenzo Librandi, Jul 06 2012

a(n) = 2*A005476(n)+1. - Bruno Berselli, Jul 06 2012

MATHEMATICA

CoefficientList[Series[(7*x^2+2*x+1)/(1-x)^3, {x, 0, 40}], x] (* Vincenzo Librandi, Jul 06 2012 *)

PROG

(MAGMA) [ 5*n^2-n+1: n in [0..50] ];

(PARI) a(n)=5*n^2-n+1 \\ Charles R Greathouse IV, Jun 17 2017

CROSSREFS

Sequence in context: A022267 A094465 A020580 * A146616 A146395 A154302

Adjacent sequences:  A172040 A172041 A172042 * A172044 A172045 A172046

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Jan 29 2010

EXTENSIONS

Replaced definition with formula. - N. J. A. Sloane, Mar 03 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 November 21 12:43 EST 2017. Contains 295001 sequences.