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) my(x='x + O('x^50)); Vec(-(12*x - 11)*(10*x - 11)/(x - 1)^3) \\ G. C. Greubel, Feb 23 2017
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Frederic Sebastian (frederic.sebastian(AT)gmail.com), Apr 24 2008
STATUS
approved