A017186 a(n) = (9*n + 2)^2.

4, 121, 400, 841, 1444, 2209, 3136, 4225, 5476, 6889, 8464, 10201, 12100, 14161, 16384, 18769, 21316, 24025, 26896, 29929, 33124, 36481, 40000, 43681, 47524, 51529, 55696, 60025, 64516, 69169

Offset

0,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

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

Formula

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3); a(0)=4, a(1)=121, a(2)=400. - Harvey P. Dale, Apr 16 2013

G.f.: ( -4 - 109*x - 49*x^2 ) / (x-1)^3. - R. J. Mathar, Jul 14 2016

Maple

seq((9*n+2)^2, n=0..30); # Muniru A Asiru, Oct 20 2018

Mathematica

(9Range[0, 30]+2)^2 (* or *) LinearRecurrence[{3, -3, 1}, {4, 121, 400}, 30] (* Harvey P. Dale, Apr 16 2013 *)

Prog

(Magma) [(9*n+2)^2: n in [0..35]]; // Vincenzo Librandi, Jul 23 2011
(PARI) a(n)=(9*n+2)^2 \\ Charles R Greathouse IV, Jun 17 2017
(GAP) List([0..30], n->(9*n+2)^2); # Muniru A Asiru, Oct 20 2018

Crossrefs

Sequence in context: A062081 A053881 A075114 * A355751 A098839 A227525

Adjacent sequences: A017183 A017184 A017185 * A017187 A017188 A017189

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved