OFFSET
0,2
LINKS
FORMULA
a(n) = 2*n^2 + 9*n.
a(n) = a(n-1) + 4*n + 7 (with a(0)=0). - Vincenzo Librandi, Nov 24 2010
MATHEMATICA
s=0; lst={s}; Do[s+=n++ +11; AppendTo[lst, s], {n, 0, 7!, 4}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 19 2008 *)
Table[Sum[(2*i + n - 1), {i, 4, n}], {n, 3, 45}] (* Zerinvary Lajos, Jul 11 2009 *)
Table[n(2n+9), {n, 0, 50}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 11, 26}, 50] (* Harvey P. Dale, Dec 18 2018 *)
PROG
(PARI) a(n)=n*(2*n+9) \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Omar E. Pol, May 19 2008
STATUS
approved