OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..5000
Index entries for linear recurrences with constant coefficients, signature (3, -3, 1).
FORMULA
a(n) = 21*n + a(n-1) - 10 for n>0, a(0)=0. - Vincenzo Librandi, Aug 04 2010
a(0)=0, a(1)=11, a(2)=43; for n>2, a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Harvey P. Dale, May 06 2014
From G. C. Greubel, Aug 23 2017: (Start)
G.f.: x*(10*x + 11)/(1-x)^3.
E.g.f.: (x/2)*(21*x + 22)*exp(x). (End)
MATHEMATICA
Table[n (21 n + 1)/2, {n, 0, 100}] (* Vladimir Joseph Stephan Orlovsky, Mar 07 2011 *)
LinearRecurrence[{3, -3, 1}, {0, 11, 43}, 40] (* Harvey P. Dale, May 06 2014 *)
PROG
(PARI) a(n)=n*(21*n+1)/2 \\ Charles R Greathouse IV, Jun 16 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved