A017246 a(n) = (9*n + 7)^2.

49, 256, 625, 1156, 1849, 2704, 3721, 4900, 6241, 7744, 9409, 11236, 13225, 15376, 17689, 20164, 22801, 25600, 28561, 31684, 34969, 38416, 42025, 45796, 49729, 53824, 58081, 62500, 67081, 71824

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..10000
• Index entries for linear recurrences with constant coefficients, signature (3, -3, 1).

Crossrefs

Cf. A000290 (n^2), A017245 (9*n+7).

Programs

Magma

[(9*n+7)^2: n in [0..35]]; // Vincenzo Librandi, Jul 27 2011

Mathematica

(9*Range[0,30]+7)^2 (* or *) LinearRecurrence[{3,-3,1},{49,256,625},30] (* Harvey P. Dale, Apr 24 2016 *)

PARI

a(n)=(9*n+7)^2 \\ Charles R Greathouse IV, Jun 17 2017

Formula

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3); a(0)=49, a(1)=256, a(2)=625. - Harvey P. Dale, Apr 24 2016

G.f.: -(49 + 109*x + 4*x^2)/(x-1)^3. - R. J. Mathar, Mar 20 2018