OFFSET
2,1
COMMENTS
LINKS
Danny Rorabaugh, Table of n, a(n) for n = 2..10000
Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).
FORMULA
a(n) = (3*n^4-2*n^3-n^2)/4. G.f.: -x^2*(x^2+10*x+7) / (x-1)^5. - Colin Barker, Jul 11 2014
EXAMPLE
a(2) = 2^3-1^3 = 7.
a(3) = (3^3-1^3) + (3^3-2^3) = 45.
MATHEMATICA
PROG
(PARI) vector(100, n, (3*n^4+10*n^3+11*n^2+4*n)/4) \\ Colin Barker, Jul 11 2014
(PARI) Vec(-x^2*(x^2+10*x+7)/(x-1)^5 + O(x^100)) \\ Colin Barker, Jul 11 2014
(Sage) [sum([n^3-j^3 for j in range(1, n)]) for n in range(2, 35)] # Danny Rorabaugh, Apr 18 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Feb 15 2012
STATUS
approved