OFFSET
4,1
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).
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
MATHEMATICA
Table[(n-3)*(n-8)/2, {n, 4, 60}] (* G. C. Greubel, Jun 15 2016 *)
PROG
(PARI) a(n)=(n-3)*(n-8)/2 \\ Charles R Greathouse IV, Jun 17 2017
(Magma) [(n-3)*(n-8)/2: n in [4..60]]; // G. C. Greubel, Jul 30 2022
(SageMath) [(n-3)*(n-8)/2 for n in (4..60)] # G. C. Greubel, Jul 30 2022
CROSSREFS
KEYWORD
sign,easy,less
AUTHOR
Jamel Ghanouchi, Nov 06 2009
EXTENSIONS
Edited and extended by R. J. Mathar, Nov 12 2009
STATUS
approved