A167544 a(n) = (n-3)*(n-8)/2.

-2, -3, -3, -2, 0, 3, 7, 12, 18, 25, 33, 42, 52, 63, 75, 88, 102, 117, 133, 150, 168, 187, 207, 228, 250, 273, 297, 322, 348, 375, 403, 432, 462, 493, 525, 558, 592, 627, 663, 700, 738, 777, 817, 858, 900, 943, 987, 1032, 1078, 1125, 1173

Offset: 4

Author

Jamel Ghanouchi, Nov 06 2009

Keywords

• sign
• easy
• less

Comments

Essentially a duplicate of A055998.

Links

• G. C. Greubel, Table of n, a(n) for n = 4..1000
• Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

Crossrefs

Cf. A027379, A055998, A135929, A137276.

Programs

Magma

[(n-3)*(n-8)/2: n in [4..60]]; // G. C. Greubel, Jul 30 2022

Mathematica

Table[(n-3)*(n-8)/2, {n,4,60}] (* G. C. Greubel, Jun 15 2016 *)

PARI

a(n)=(n-3)*(n-8)/2 \\ Charles R Greathouse IV, Jun 17 2017

SageMath

[(n-3)*(n-8)/2 for n in (4..60)] # G. C. Greubel, Jul 30 2022

Formula

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3).

G.f.: x^4*(-2 + 3*x)/(1-x)^3.

a(n) = A055998(n-8). - Philippe Deléham, Nov 25 2009

a(n) = a(n-1) + n - 6 (with a(4)=-2). - Vincenzo Librandi, Dec 05 2010

a(n) = A027379(n-8) for n >= 9. - Georg Fischer, Oct 24 2018

E.g.f.: (1/2)*( (24 -10*x + x^2)*exp(x) - (24 + 14*x + 3*x^2) ). - G. C. Greubel, Jul 30 2022

Extensions

Edited and extended by R. J. Mathar, Nov 12 2009