A155661 a(n) = 10^n - 7^n + 1.

1, 4, 52, 658, 7600, 83194, 882352, 9176458, 94235200, 959646394, 9717524752, 98022673258, 986158712800, 9903110989594, 99321776927152, 995252438490058, 9966767069430400, 99767369486012794, 998371586402089552

Offset

0,2

Links

Table of n, a(n) for n=0..18.

Index entries for linear recurrences with constant coefficients, signature (18,-87,70).

Formula

G.f.: 1/(1-10*x)-1/(1-7*x)+1/(1-x).

E.g.f.: e^(10*x)-e^(7*x)+e^x.

a(n) = 17*a(n-1)-70*a(n-2)+54 with a(0)=1, a(1)=4. - Vincenzo Librandi, Jul 21 2010

a(0)=1, a(1)=4, a(2)=52, a(n)=18*a(n-1)-87*a(n-2)+70*a(n-3). - Harvey P. Dale, May 05 2011

Mathematica

Table[10^n-7^n+1, {n, 0, 20}] (* or *) LinearRecurrence[{18, -87, 70}, {1, 4, 52}, 21] (* Harvey P. Dale, May 05 2011 *)

Prog

(PARI) a(n)=10^n-7^n+1 \\ Charles R Greathouse IV, Jun 11 2015

Crossrefs

Cf. A155638, A155639, A155640, A155641, A155642, A155643, A155644, A155645, A155646, A155647, A155648, A155649, A155650, A155651, A155652, A155653, A155654, A155655, A155656, A155657, A155658, A155659, A155660.

Sequence in context: A247746 A221727 A144339 * A198281 A220933 A222321

Adjacent sequences: A155658 A155659 A155660 * A155662 A155663 A155664

Keyword

nonn,easy

Author

Mohammad K. Azarian, Jan 31 2009

Status

approved