A024108 a(n) = 9^n-n^7.

1, 8, -47, -1458, -9823, -19076, 251505, 3959426, 40949569, 382637520, 3476784401, 31361572438, 282393704673, 2541803079812, 22876687041457, 205890961235274, 1853019920416385, 16677181289327896, 150094634684779089, 1350851716779120350

Offset: 0

Author

N. J. A. Sloane

Keywords

• sign
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..400
• Index entries for linear recurrences with constant coefficients, signature (17,-100,308,-574,686,-532,260,-73,9).

Programs

Magma

[9^n-n^7: n in [0..25]]; // Vincenzo Librandi, Jul 06 2011

Mathematica

Table[9^n - n^7, {n, 0, 19}] (* Michael De Vlieger, Mar 20 2015 *)
LinearRecurrence[{17,-100,308,-574,686,-532,260,-73,9},{1,8,-47,-1458,-9823,-19076,251505,3959426,40949569},20] (* Harvey P. Dale, Mar 23 2018 *)

PARI

Vec(-(10*x^8+1071*x^7+10627*x^6+20497*x^5+8373*x^4-167*x^3-83*x^2-9*x+1)/((x-1)^8*(9*x-1)) + O(x^100)) \\ Colin Barker, Mar 20 2015

Formula

G.f.: -(10*x^8+1071*x^7+10627*x^6+20497*x^5+8373*x^4-167*x^3-83*x^2-9*x+1) / ((x-1)^8*(9*x-1)). - Colin Barker, Mar 20 2015

a(n) = A001019(n) - A001015(n). - Michel Marcus, Mar 20 2015