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

 

Logo

Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A126719 a(n) = -n^2 + 9n + 23. 7
23, 31, 37, 41, 43, 43, 41, 37, 31, 23, 13, 1, -13, -29, -47, -67, -89, -113, -139, -167, -197, -229, -263, -299, -337, -377, -419, -463, -509, -557, -607, -659, -713, -769, -827, -887, -949, -1013, -1079, -1147, -1217, -1289, -1363, -1439, -1517, -1597, -1679, -1763, -1849, -1937, -2027, -2119, -2213 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Derivation is similar to that of A126665, which see for further information.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Michael M. Ross, Natural Numbers

Robert Sacks, Number Spiral: Method of Common Differences

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

FORMULA

a(n) = 3*a(n-1)-3*a(n-2)+a(n-3), a(0)=23, a(1)=31, a(2)=37. [Harvey P. Dale, Oct 19 2011]

G.f.: ((38-13*x)*x-23)/(x-1)^3. [Harvey P. Dale, Oct 19 2011]

EXAMPLE

For n=8, -1*8^2 + 9*8 + 23 = 31.

MAPLE

A126719:=n->-n^2+9*n+23: seq(A126719(n), n=0..100); # Wesley Ivan Hurt, Jan 20 2017

MATHEMATICA

Table[-n^2+9n+23, {n, 0, 60}] (* or *) LinearRecurrence[{3, -3, 1}, {23, 31, 37}, 60] (* Harvey P. Dale, Oct 19 2011 *)

PROG

(PARI) a(n)=-n^2+9*n+23 \\ Charles R Greathouse IV, Oct 07 2015

CROSSREFS

Cf. A126665.

Sequence in context: A036267 A107934 A155107 * A110677 A169640 A026051

Adjacent sequences:  A126716 A126717 A126718 * A126720 A126721 A126722

KEYWORD

sign,easy

AUTHOR

Michael M. Ross, Mar 13 2007

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 December 15 11:05 EST 2018. Contains 318148 sequences. (Running on oeis4.)