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A024077 7^n - n^2. 2
1, 6, 45, 334, 2385, 16782, 117613, 823494, 5764737, 40353526, 282475149, 1977326622, 13841287057, 96889010238, 678223072653, 4747561509718, 33232930569345, 232630513986918, 1628413597910125, 11398895185372782 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (10,-24,22,-7).

FORMULA

G.f.: (1-4*x+9*x^2+6*x^3)/((1-7*x)*(1-x)^3). - Vincenzo Librandi, Oct 06 2014

a(n) = 10*a(n-1) -24*a(n-2) +22*a(n-3) -7*a(n-4) for n>3. - Vincenzo Librandi, Oct 06 2014

MATHEMATICA

Table[7^n - n^2, {n, 0, 25}] (* or *) CoefficientList[Series[(1 - 4 x + 9 x^2 + 6 x^3)/((1 - 7 x) (1 - x)^3), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 06 2014 *)

PROG

(MAGMA) [7^n-n^2: n in [0..25]]; // Vincenzo Librandi, Jul 03 2011

(PARI) a(n)=7^n-n^2 \\ Charles R Greathouse IV, Oct 06 2014

CROSSREFS

Cf. similar sequences listed in A024025.

Sequence in context: A201191 A214982 A189801 * A097129 A048663 A095003

Adjacent sequences:  A024074 A024075 A024076 * A024078 A024079 A024080

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified December 1 01:37 EST 2021. Contains 349426 sequences. (Running on oeis4.)