A164827 Generalized Lucas numbers: a(n) = a(n-1) + 10*a(n-2); with a(1)=2 a(2)=1.

2, 1, 21, 31, 241, 551, 2961, 8471, 38081, 122791, 503601, 1731511, 6767521, 24082631, 91757841, 332584151, 1250162561, 4576004071, 17077629681, 62837670391, 233613967201, 861990671111, 3198130343121, 11818037054231

Offset: 1

Author

Mark Dols, Aug 27 2009

Keywords

• nonn
• easy

Links

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

Crossrefs

Cf. A000032, A015446.

Programs

Mathematica

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

Formula

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

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

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