A139612 a(n) = 66*n + 12.

12, 78, 144, 210, 276, 342, 408, 474, 540, 606, 672, 738, 804, 870, 936, 1002, 1068, 1134, 1200, 1266, 1332, 1398, 1464, 1530, 1596, 1662, 1728, 1794, 1860, 1926, 1992, 2058, 2124, 2190, 2256, 2322, 2388, 2454, 2520, 2586, 2652, 2718

Offset

0,1

Comments

Numbers of the 12th column of positive numbers in the square array of nonnegative and polygonal numbers A139600. Also, numbers of the 12th column in the square array A057145.

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..5000

Index entries for linear recurrences with constant coefficients, signature (2,-1).

Formula

From Elmo R. Oliveira, Apr 03 2024: (Start)

G.f.: 6*(2+9*x)/(x-1)^2.

E.g.f.: 6*exp(x)*(2 + 11*x).

a(n) = 6*A017413(n).

a(n) = 2*a(n-1) - a(n-2) for n >= 2. (End)

Mathematica

66*Range[0, 50]+12 (* or *) LinearRecurrence[{2, -1}, {12, 78}, 50] (* Harvey P. Dale, Jun 14 2017 *)

Prog

(Magma) [6*(11*n + 2): n in [0..60]]; // Vincenzo Librandi, Jul 23 2011
(PARI) a(n)=66*n+12 \\ Charles R Greathouse IV, Oct 05 2011

Crossrefs

Cf. A017413, A057145, A139600.

Sequence in context: A109711 A244390 A136540 * A304503 A268793 A162629

Adjacent sequences: A139609 A139610 A139611 * A139613 A139614 A139615

Keyword

easy,nonn

Author

Omar E. Pol, Apr 27 2008

Status

approved