A083423 - OEIS

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A083423

(5*3^n+(-3)^n)/6.

1, 2, 9, 18, 81, 162, 729, 1458, 6561, 13122, 59049, 118098, 531441, 1062882, 4782969, 9565938, 43046721, 86093442, 387420489, 774840978, 3486784401, 6973568802, 31381059609, 62762119218, 282429536481, 564859072962 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	LINKS	`Index to sequences with linear recurrences with constant coefficients, signature (0,9)`
	FORMULA	`G.f.: (1+2x)/((1-3x)(1+3x)). E.g.f.: (5exp(3x)+exp(-3x))/6` `a(n+3) = a(n+2)a(n+1)/a(n). [Reinhard Zumkeller, Mar 04 2011]` `a(n) = 9a(n-2). - Vincenzo Librandi, Mar 20 2011`
	CROSSREFS	`Cf. A083424.` `Sequence in context: A083708 A191520 A037421 * A068978 A006226 A109298` `Adjacent sequences: A083420 A083421 A083422 * A083424 A083425 A083426`
	KEYWORD	`easy,nonn`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Apr 30 2003`

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Last modified February 16 19:46 EST 2012. Contains 205952 sequences.