A136169 - OEIS

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A136169

a(n) = 2*a(n-1) - [(n+1)/3] for n>0 with a(0) = 1.

1, 2, 3, 5, 9, 16, 30, 58, 113, 223, 443, 882, 1760, 3516, 7027, 14049, 28093, 56180, 112354, 224702, 449397, 898787, 1797567, 3595126, 7190244, 14380480, 28760951, 57521893, 115043777, 230087544, 460175078, 920350146, 1840700281, 3681400551 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	FORMULA	`G.f. A(x) = (1 - x^2(1+x+x^2)/(1-x^3)^2 )/(1-2x).`
	PROG	`(PARI) {a(n)=if(n==0, 1, 2*a(n-1)-((n+1)\3))}`
	CROSSREFS	`Cf. A136219.` `Sequence in context: A050168 A072176 A047061 * A047041 A154223 A061031` `Adjacent sequences: A136166 A136167 A136168 * A136170 A136171 A136172`
	KEYWORD	`nonn`
	AUTHOR	`Paul D. Hanna (pauldhanna(AT)juno.com), Dec 23 2007`

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Last modified February 13 23:23 EST 2012. Contains 205567 sequences.