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A164827 Generalized Lucas numbers: a(n) = a(n-1) + 10 a(n-2); with a(1)=2 a(2)=1 0
2, 1, 21, 31, 241, 551, 2961, 8471, 38081, 122791, 503601, 1731511, 6767521, 24082631, 91757841, 332584151, 1250162561, 4576004071, 17077629681, 62837670391, 233613967201, 861990671111, 3198130343121, 11818037054231 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..24.

Index entries for linear recurrences with constant coefficients, signature (1,10).

FORMULA

a(n) = [(1/2)-(1/2)*sqrt(41)]^(n-1)+[(1/2)+(1/2)*sqrt(41)]^(n-1), with n>=1. [Paolo P. Lava, Dec 03 2009]

G.f.: x*(2-x)/(1-x-10*x^2). [Colin Barker, Jun 17 2012]

a(1)=2, a(2)=1, a(n) = a(n-1)+10*a(n-2). - Harvey P. Dale, Apr 07 2015

a(n) = 2*A015446(n-1) - A015446(n-2). - R. J. Mathar, Oct 08 2016

MATHEMATICA

LinearRecurrence[{1, 10}, {2, 1}, 30] (* Harvey P. Dale, Apr 07 2015 *)

CROSSREFS

Cf. A000032, A015446

Sequence in context: A191719 A009768 A051492 * A213976 A200859 A127607

Adjacent sequences:  A164824 A164825 A164826 * A164828 A164829 A164830

KEYWORD

nonn,easy

AUTHOR

Mark Dols, Aug 27 2009

STATUS

approved

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Last modified October 21 23:02 EDT 2018. Contains 316431 sequences. (Running on oeis4.)