OFFSET
8,1
LINKS
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
a(n) = Sum_{k=8..n} k*(k+1)/2-30.
Binomial transform of [6, 15, 10, 1, 0, 0, 0, ...]. - Gary W. Adamson, Oct 22 2007
From R. J. Mathar, May 17 2008: (Start)
O.g.f.: -x^8*(-6 + 3*x + 2*x^2)/(-1+x)^4.
a(n+1) - a(n) = A051940(n+1).
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)
MATHEMATICA
LinearRecurrence[{4, -6, 4, -1}, {6, 21, 46, 82}, 50] (* Harvey P. Dale, Oct 20 2013 *)
PROG
(PARI) a(n)=(n-7)*(n^2+10*n-108)/6 \\ Charles R Greathouse IV, Nov 10 2015
(Magma) [(n-7)*(n^2+10*n-108)/6 : n in [8..70]]; // Wesley Ivan Hurt, Apr 20 2021
CROSSREFS
KEYWORD
easy,nice,nonn
AUTHOR
Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Dec 21 1999
STATUS
approved