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A072329 a(n+1)=3*a(n-2)+2*a(n-1) a(n)=x^n+y^n+z^n. 0
3, 0, 4, 9, 8, 30, 43, 84, 176, 297, 604, 1122, 2099, 4056, 7564, 14409, 27296, 51510, 97819, 184908, 350168, 663273, 1255060, 2377050 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

With the terms indexed as shown, has property that n prime or n=2^k or n=3^k => n divides a(n).

LINKS

Table of n, a(n) for n=0..23.

FORMULA

a(n)=x^n+y^n+z^n e=-1/2+i*sqrt(3)/2, e^2=-1/2-i*sqrt(3)/2 x=((3+sqrt(9-32/27)/2)^(1/3)+((3-sqrt(9-32/27))/2)^(1/3) y=e*((3+sqrt(9-32/27))/2)^(1/3)+(e^2)*((3-sqrt(9-32/27))/2)^(1/3) z=(e^2)*((3+sqrt(9-32/27)/2)^(1/3)+e*((3-sqrt(9-32/27))/2)^(1/3)

G.f.: g(x)=(3-2*x^2)/(1-2*x^2-3*x^3)

CROSSREFS

Cf. A001608.

Sequence in context: A088230 A181482 A330420 * A068630 A309764 A079406

Adjacent sequences:  A072326 A072327 A072328 * A072330 A072331 A072332

KEYWORD

easy,nonn

AUTHOR

Miklos Kristof, Jul 15 2002

EXTENSIONS

Corrected by T. D. Noe, Nov 07 2006

STATUS

approved

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Last modified April 1 02:15 EDT 2020. Contains 333153 sequences. (Running on oeis4.)