A155673 a(n) = 11^n + 10^n - 1.

1, 20, 220, 2330, 24640, 261050, 2771560, 29487170, 314358880, 3357947690, 35937424600, 385311670610, 4138428376720, 44522712143930, 479749833583240, 5177248169415650, 55949729863572160, 605447028499293770

Offset

0,2

Links

Table of n, a(n) for n=0..17.

Index entries for linear recurrences with constant coefficients, signature (22,-131,110).

Formula

G.f.: 1/(1-11*x)+1/(1-10*x)-1/(1-x).

E.g.f.: e^(11*x)+e^(10*x)-e^x.

a(n) = 21*a(n-1)-110*a(n-2)-90 with a(0)=1, a(1)=20. - Vincenzo Librandi, Jul 21 2010

a(n) = 22*a(n-1)-131*a(n-2)+110*a(n-3). - Wesley Ivan Hurt, May 19 2024

Mathematica

Table[11^n+10^n-1, {n, 0, 20}] (* Harvey P. Dale, Feb 24 2011 *)

Crossrefs

Cf. A155654, A155655, A155656, A155657, A155658, A155659, A155660, A155661, A155662, A155663, A155664, A155665, A155666, A155667, A155668, A155669, A155670, A155671, A155672.

Sequence in context: A341371 A004411 A140354 * A000833 A302661 A178261

Adjacent sequences: A155670 A155671 A155672 * A155674 A155675 A155676

Keyword

nonn,easy

Author

Mohammad K. Azarian, Feb 01 2009

Status

approved