A139577 a(n) = n*(2*n + 11).

0, 13, 30, 51, 76, 105, 138, 175, 216, 261, 310, 363, 420, 481, 546, 615, 688, 765, 846, 931, 1020, 1113, 1210, 1311, 1416, 1525, 1638, 1755, 1876, 2001, 2130, 2263, 2400, 2541, 2686, 2835, 2988, 3145, 3306, 3471, 3640, 3813, 3990

Offset

0,2

Links

Table of n, a(n) for n=0..42.

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

Formula

a(n) = 2*n^2 + 11*n.

a(n) = a(n-1) + 4*n + 9 (with a(0)=0). - Vincenzo Librandi, Nov 24 2010

Mathematica

s=0; lst={s}; Do[s+=n++ +13; AppendTo[lst, s], {n, 0, 7!, 4}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 19 2008 *)
Table[n(2n+11), {n, 0, 50}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 13, 30}, 50] (* Harvey P. Dale, Mar 17 2019 *)

Prog

(PARI) a(n)=n*(2*n+11) \\ Charles R Greathouse IV, Jun 17 2017

Crossrefs

Cf. A014105, A014106, A033537, A130861, A139576, A139578, A139579, A139580, A139581.

Sequence in context: A104817 A048450 A216193 * A172463 A329950 A183445

Adjacent sequences: A139574 A139575 A139576 * A139578 A139579 A139580

Keyword

easy,nonn

Author

Omar E. Pol, May 19 2008

Status

approved