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A139578
a(n) = n(2n+13).
6
0, 15, 34, 57, 84, 115, 150, 189, 232, 279, 330, 385, 444, 507, 574, 645, 720, 799, 882, 969, 1060, 1155, 1254, 1357, 1464, 1575, 1690, 1809, 1932, 2059, 2190, 2325, 2464, 2607, 2754, 2905, 3060, 3219, 3382, 3549, 3720, 3895, 4074
OFFSET
0,2
FORMULA
a(n) = 2*n^2 + 13*n.
a(n) = a(n-1) + 4*n + 11 (with a(0)=0). - Vincenzo Librandi, Nov 24 2010
MATHEMATICA
s=0; lst={s}; Do[s+=n++ +15; AppendTo[lst, s], {n, 0, 7!, 4}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 19 2008 *)
Table[n(2n+13), {n, 0, 50}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 15, 34}, 50] (* Harvey P. Dale, Nov 22 2014 *)
PROG
(PARI) a(n)=n*(2*n+13) \\ Charles R Greathouse IV, Oct 07 2015
KEYWORD
easy,nonn
AUTHOR
Omar E. Pol, May 19 2008
STATUS
approved