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A137517 a(0) = 121; for n>0, a(n) = a(n-1) - n + 1. 1
121, 121, 120, 118, 115, 111, 106, 100, 93, 85, 76, 66, 55, 43, 30, 16, 1, -15, -32, -50, -69, -89, -110, -132, -155, -179, -204, -230, -257, -285, -314, -344, -375, -407, -440, -474, -509, -545, -582, -620, -659, -699, -740, -782, -825, -869, -914, -960 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

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

FORMULA

a(n) = (1/2)*(242 - n^2 + n) - Alexander R. Povolotsky, Apr 26 2008

a(0)=121, a(1)=121, a(2)=120, a(n)=3*a(n-1)-3*a(n-2)+a(n-3). - Harvey P. Dale, Dec 07 2012

G.f.: -(12*x-11)*(10*x-11) / (x-1)^3 . - R. J. Mathar, Nov 07 2015

MATHEMATICA

RecurrenceTable[{a[0]==121, a[n]==a[n-1]-n+1}, a, {n, 60}] (* or *) LinearRecurrence[{3, -3, 1}, {121, 121, 120}, 60] (* Harvey P. Dale, Dec 07 2012 *)

CoefficientList[Series[-(12*x - 11)*(10*x - 11)/(x - 1)^3, {x, 0, 50}], x] (* G. C. Greubel, Feb 23 2017 *)

PROG

(PARI) x='x + O('x^50); Vec(-(12*x - 11)*(10*x - 11)/(x - 1)^3) \\ _G. C. Greubl_, Feb 23 2017

CROSSREFS

Sequence in context: A202003 A109838 A014734 * A014735 A137850 A262517

Adjacent sequences:  A137514 A137515 A137516 * A137518 A137519 A137520

KEYWORD

sign,easy

AUTHOR

Frederic Sebastian (frederic.sebastian(AT)gmail.com), Apr 24 2008

STATUS

approved

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Last modified May 8 05:23 EDT 2021. Contains 343653 sequences. (Running on oeis4.)