A214660 a(n) = 9*n^2 - 11*n + 3.

1, 17, 51, 103, 173, 261, 367, 491, 633, 793, 971, 1167, 1381, 1613, 1863, 2131, 2417, 2721, 3043, 3383, 3741, 4117, 4511, 4923, 5353, 5801, 6267, 6751, 7253, 7773, 8311, 8867, 9441, 10033, 10643, 11271, 11917, 12581, 13263, 13963, 14681, 15417, 16171, 16943

Offset

1,2

Comments

Central terms of triangle A214604.

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

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

Formula

G.f.: (1+14*x+3*x^2)/(1-x)^3. - Harvey P. Dale, Aug 29 2021

E.g.f.: -3 + (3 - 2*x + 9*x^2)*exp(x). - G. C. Greubel, Mar 09 2024

Mathematica

Table[9n^2-11n+3, {n, 60}] (* or *) LinearRecurrence[{3, -3, 1}, {1, 17, 51}, 60] (* Harvey P. Dale, Aug 29 2021 *)

Prog

(Haskell)
a214660 n = (9 * n - 11) * n + 3
(PARI) a(n)=9*n^2-11*n+3 \\ Charles R Greathouse IV, Jun 17 2017
(Magma) [9*n^2-11*n+3: n in [1..60]]; // G. C. Greubel, Mar 09 2024
(SageMath) [9*n^2-11*n+3 for n in range(1, 61)] # G. C. Greubel, Mar 09 2024

Crossrefs

Cf. A214604, A214675.

Sequence in context: A003124 A005570 A195037 * A258598 A223906 A146673

Adjacent sequences: A214657 A214658 A214659 * A214661 A214662 A214663

Keyword

nonn,easy

Author

Reinhard Zumkeller, Jul 25 2012

Status

approved