A017558 a(n) = (12*n + 3)^2.

9, 225, 729, 1521, 2601, 3969, 5625, 7569, 9801, 12321, 15129, 18225, 21609, 25281, 29241, 33489, 38025, 42849, 47961, 53361, 59049, 65025, 71289, 77841, 84681, 91809, 99225, 106929, 114921, 123201

Offset

0,1

Links

Table of n, a(n) for n=0..29.

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

Formula

G.f.: 9*(1 + 22*x + 9*x^2)/(1-x)^3.

a(n) = 9*A016814(n).

a(n) = a(n-1) + 288*n - 72, n >= 1. - Vincenzo Librandi, Mar 20 2011

Mathematica

(12*Range[0, 30]+3)^2 (* or *) LinearRecurrence[{3, -3, 1}, {9, 225, 729}, 30] (* Harvey P. Dale, Aug 04 2015 *)

Prog

(PARI) a(n)=(12*n+3)^2 \\ Charles R Greathouse IV, Jun 17 2017

Crossrefs

Sequence in context: A120319 A057530 A014736 * A159939 A167038 A074190

Adjacent sequences: A017555 A017556 A017557 * A017559 A017560 A017561

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved