A156341 Expansion of (2-6*x)/(1-12*x+11*x^2).

2, 18, 194, 2130, 23426, 257682, 2834498, 31179474, 342974210, 3772716306, 41499879362, 456498672978, 5021485402754, 55236339430290, 607599733733186, 6683597071065042, 73519567781715458, 808715245598870034, 8895867701587570370, 97854544717463274066

Offset

0,1

Links

Harvey P. Dale, Table of n, a(n) for n = 0..960

Tomislav Došlić and Frode Måløy, Chain hexagonal cacti: Matchings and independent sets, Discr. Math., 310 (2010), 1676-1690.

Index entries for linear recurrences with constant coefficients, signature (12,-11).

Formula

From Felix P. Muga II, Mar 19 2014: (Start)

a(n) = 12*a(n-1)-11*a(n-2) for n>=2, a(0)=2, a(1)=18.

a(n) = a(n-1)+16*11^(n-1) for n >=1, a(0)=2.

a(n) = 10*a(n-1)+11*a(n-2)-8 for n>=2, a(0)=2, a(1)=18.

a(n) = (8/5)*11^n + 2/5. (End)

Mathematica

CoefficientList[Series[(2-6x)/(1-12x+11x^2), {x, 0, 40}], x] (* or *) LinearRecurrence[{12, -11}, {2, 18}, 40] (* Harvey P. Dale, Jan 27 2022 *)

Crossrefs

Sequence in context: A362992 A155542 A157765 * A262718 A210989 A361877

Adjacent sequences: A156338 A156339 A156340 * A156342 A156343 A156344

Keyword

nonn,easy

Author

N. J. A. Sloane, May 22 2010

Status

approved