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A135263 a(n) = 2*A132357(n). 1
2, 8, 28, 82, 244, 728, 2186, 6560, 19684, 59050, 177148, 531440, 1594322, 4782968, 14348908, 43046722, 129140164, 387420488, 1162261466, 3486784400, 10460353204, 31381059610, 94143178828, 282429536480, 847288609442 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Digital roots yield a hexaperiodic sequence A010888(a(n))= 2, (8, 1, 1, 1, 8, 8,...), the period of length 6 put in parenthesis. Digital roots of A132357 are also hexaperiodic: 1, (4, 5, 5, 5, 4, 4, ....).

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (3,0,-1,3).

FORMULA

a(n) = 3*a(n-1) - a(n-3) + a(n-4).

G.f.: 2*(1+x+2*x^2)/((1+x)*(1-3*x)*(1-x+x^2)). - Colin Barker, Jun 16 2012

MATHEMATICA

LinearRecurrence[{3, 0, -1, 3}, {2, 8, 28, 82}, 50] (* G. C. Greubel, Oct 07 2016 *)

CROSSREFS

Cf. A133448 (hexaperiodic sequence of digital roots).

Sequence in context: A245996 A229935 A082107 * A048497 A118047 A087431

Adjacent sequences:  A135260 A135261 A135262 * A135264 A135265 A135266

KEYWORD

nonn,less,easy

AUTHOR

Paul Curtz, Dec 02 2007

EXTENSIONS

Edited and extended by R. J. Mathar, Jul 22 2008

STATUS

approved

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Last modified October 20 20:24 EDT 2019. Contains 328273 sequences. (Running on oeis4.)