A024043 a(n) = 4^n - n^7.

1, 3, -112, -2123, -16128, -77101, -275840, -807159, -2031616, -4520825, -8951424, -15292867, -19054592, 4360347, 163021952, 902882449, 4026531840, 16769530511, 68107256704, 273984035205, 1098231627776

Offset: 0

Author

N. J. A. Sloane

Keywords

• sign
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..500

Programs

Magma

[4^n-n^7: n in [0..30]]; // Vincenzo Librandi, Jul 02 2011

Mathematica

Table[4^n-n^7,{n,0,20}]  (* Harvey P. Dale, Mar 24 2011 *)

Formula

From Chai Wah Wu, Jan 26 2020: (Start)

a(n) = 12*a(n-1) - 60*a(n-2) + 168*a(n-3) - 294*a(n-4) + 336*a(n-5) - 252*a(n-6) + 120*a(n-7) - 33*a(n-8) + 4*a(n-9) for n > 8.

G.f.: (-5*x^8 - 471*x^7 - 4672*x^6 - 8417*x^5 - 2418*x^4 + 767*x^3 + 88*x^2 + 9*x - 1)/((x - 1)^8*(4*x - 1)). (End)