A152965 Twice 12-gonal numbers: a(n) = 2*n*(5*n-4).

0, 2, 24, 66, 128, 210, 312, 434, 576, 738, 920, 1122, 1344, 1586, 1848, 2130, 2432, 2754, 3096, 3458, 3840, 4242, 4664, 5106, 5568, 6050, 6552, 7074, 7616, 8178, 8760, 9362, 9984, 10626, 11288, 11970, 12672, 13394, 14136, 14898, 15680

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

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

Formula

a(n) = 2 * A051624(n).

G.f.: 2*x*(1+9*x)/(1-x)^3. - Vincenzo Librandi, Jul 10 2012

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Vincenzo Librandi, Jul 10 2012

Mathematica

s=0; lst={s}; Do[s+=n; AppendTo[lst, s], {n, 2, 6!, 20}]; lst (* Vladimir Joseph Stephan Orlovsky, Apr 02 2009 *)
Table[10*n^2-8*n, {n, 0, 50}] (* Vincenzo Librandi, Jul 10 2012 *)
LinearRecurrence[{3, -3, 1}, {0, 2, 24}, 60] (* Harvey P. Dale, Apr 18 2016 *)

Prog

(Magma) [10*n^2-8*n: n in [0..50]]; // Klaus Brockhaus, Nov 27 2010
(PARI) a(n)=2*n*(5*n-4) \\ Charles R Greathouse IV, Oct 07 2015

Crossrefs

Cf. A051624 (12-gonal numbers).

Cf. numbers of the form n*(n*k - k + 4))/2 listed in A226488 (this sequence is the case k=20). - Bruno Berselli, Jun 10 2013

Sequence in context: A292162 A068878 A100918 * A345692 A139284 A003614

Adjacent sequences: A152962 A152963 A152964 * A152966 A152967 A152968

Keyword

easy,nonn

Author

Omar E. Pol, Dec 21 2008

Status

approved