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A024064
a(n) = 6^n - n^2.
2
1, 5, 32, 207, 1280, 7751, 46620, 279887, 1679552, 10077615, 60466076, 362796935, 2176782192, 13060693847, 78364163900, 470184984351, 2821109907200, 16926659444447, 101559956668092, 609359740010135
OFFSET
0,2
FORMULA
a(0)=1, a(1)=5, a(2)=32, a(3)=207, a(n)=9*a(n-1)-21*a(n-2)+19*a(n-3)- 6*a(n-4). - Harvey P. Dale, Mar 26 2014
G.f.: (5*x^3+8*x^2-4*x+1)/((x-1)^3*(6*x-1)). - Harvey P. Dale, Mar 26 2014
MATHEMATICA
Table[6^n-n^2, {n, 0, 20}] (* or *) LinearRecurrence[{9, -21, 19, -6}, {1, 5, 32, 207}, 20] (* Harvey P. Dale, Mar 26 2014 *)
PROG
(Magma) [6^n-n^2: n in [0..25]]; // Vincenzo Librandi, Jul 03 2011
CROSSREFS
Sequence in context: A015541 A345684 A297068 * A164594 A305312 A199486
KEYWORD
nonn,easy
STATUS
approved