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!)
A190576 n^2+5*n-5. 2
1, 9, 19, 31, 45, 61, 79, 99, 121, 145, 171, 199, 229, 261, 295, 331, 369, 409, 451, 495, 541, 589, 639, 691, 745, 801, 859, 919, 981, 1045, 1111, 1179, 1249, 1321, 1395, 1471, 1549, 1629, 1711, 1795, 1881, 1969, 2059, 2151, 2245, 2341 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n)=n^2+k*n-k, A000290 for k=0, A028387 for k=1, A028872 for k=2, A082111 for k=3, A028884 for k=4.

Also a(n) = n^2+9*n+9 if the offset is changed to -1. - R. J. Mathar, May 18 2011

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

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

FORMULA

G.f. x*(-1-6*x+5*x^2) / (x-1)^3. - R. J. Mathar, May 18 2011

a(1)=1, a(2)=9, a(3)=19, a(n)=3*a(n-1)-3*a(n-2)+a(n-3). - Harvey P. Dale, May 28 2015

MATHEMATICA

k = 5; Table[n^2 + k*n - k, {n, 100}]

LinearRecurrence[{3, -3, 1}, {1, 9, 19}, 50] (* Harvey P. Dale, May 28 2015 *)

PROG

(MAGMA) [n^2+5*n-5: n in [1..50]]; // Vincenzo Librandi, Sep 30 2011

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

CROSSREFS

Cf. A000290, A028387, A028872, A082111, A028884.

Sequence in context: A189798 A056126 A190513 * A250663 A274590 A051811

Adjacent sequences:  A190573 A190574 A190575 * A190577 A190578 A190579

KEYWORD

nonn,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, May 12 2011

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 18 10:33 EST 2017. Contains 294887 sequences.