OFFSET
7,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 7..1000
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
a(n) = n(2n^2-15n+109)/6. - Ralf Stephan, Apr 30 2004
G.f.: x^7*(119-320*x+294*x^2-91*x^3)/(1-x)^4. - Colin Barker, Sep 17 2012
MATHEMATICA
CoefficientList[Series[(119 - 320 x + 294 x^2 - 91 x^3)/(1 - x)^4, {x, 0, 60}], x] (* Vincenzo Librandi, Oct 17 2013 *)
PROG
(Magma) [n*(2*n^2-15*n+109)/6: n in [7..60]]; // Vincenzo Librandi, Oct 17 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved