OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..400
FORMULA
G.f.: (10*x^4 + 31*x^3 + 11*x^2 - 5*x + 1)/((1-9*x)*(1-x)^4). - M. F. Hasler, Jun 14 2008
PROG
(Magma) [9^n-n^3: n in [0..25]]; // Vincenzo Librandi, Jul 06 2011
(PARI) a(n) = 9^n-n^3; \\ Altug Alkan, Oct 08 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved