A024090 8^n-n^2.

1, 7, 60, 503, 4080, 32743, 262108, 2097103, 16777152, 134217647, 1073741724, 8589934471, 68719476592, 549755813719, 4398046510908, 35184372088607, 281474976710400, 2251799813684959, 18014398509481660

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..400

Index entries for linear recurrences with constant coefficients, signature (11,-27,25,-8).

Formula

G.f.: (1-4*x+10*x^2+7*x^3)/((1-8*x)*(1-x)^3). - Vincenzo Librandi, Oct 06 2014

a(n) = 11*a(n-1) -27*a(n-2) +25*a(n-3) -8*a(n-4) for n>3. - Vincenzo Librandi, Oct 06 2014

a(n) = A001018(n) - A000290(n). - Michel Marcus, Oct 06 2014

Mathematica

Table[8^n - n^2, {n, 0, 25}] (* or *) CoefficientList[Series[(1 - 4 x + 10 x^2 + 7 x^3)/((1 - 8 x) (1 - x)^3), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 06 2014 *)
LinearRecurrence[{11, -27, 25, -8}, {1, 7, 60, 503}, 30] (* Harvey P. Dale, Feb 13 2023 *)

Prog

(Magma) [8^n-n^2: n in [0..20]]; // Vincenzo Librandi, Jul 05 2011

Crossrefs

Cf. similar sequences listed in A024025.

Sequence in context: A303120 A015570 A290756 * A241770 A243695 A210988

Adjacent sequences: A024087 A024088 A024089 * A024091 A024092 A024093

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved