OFFSET
0,2
COMMENTS
For n>1, a(n) is the volume of a truncated square pyramid with height n and base lengths n+2 and n-1. - Wesley Ivan Hurt, Apr 05 2016
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
D. Applegate, M. LeBrun, N. J. A. Sloane, Dismal Arithmetic, J. Int. Seq. 14 (2011) # 11.9.8.
Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets
Eric Weisstein's World of Mathematics, Magic Circles - Eric W. Weisstein, Feb 06 2009
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
O.g.f.: x*(3 + 2*x + x^2)/(1 - x)^4. - R. J. Mathar, Feb 04 2008
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>3. - Wesley Ivan Hurt, Apr 05 2016
EXAMPLE
For n = 4, 4^3 + 4^2 + 4 = 64 + 16 + 4 = 84.
MAPLE
MATHEMATICA
Table[n^3 + n^2 + n, {n, 0, 50}] (* Harvey P. Dale, Dec 13 2013 *)
PROG
(Magma) [n^3 + n^2 + n: n in [0..50]]; // Vincenzo Librandi, Jun 09 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Patrick De Geest, Mark Milhet (mm992395(AT)shellus.com)
STATUS
approved