A033489 - OEIS

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A033489

a(1) = 1, a(n) = 2*a(n-1) + a([n/2]).

1, 3, 7, 17, 37, 81, 169, 355, 727, 1491, 3019, 6119, 12319, 24807, 49783, 99921, 200197, 401121, 802969, 1607429, 3216349, 6435717, 12874453, 25755025, 51516169, 103044657, 206101633, 412228073, 824480953, 1649011689 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	MAPLE	`A033489 := proc(n) option remember; if n = 1 then 1 else A033489(n-1)+A033489(round(2*(n-1)/2))+A033489(round((n-1)/2)); fi; end;`
	PROG	`(PARI) a(n)=if(n<2, 1, (2*a(n-1)+a(floor(n/2))))`
	CROSSREFS	`Sequence in context: A026646 A026668 A111210 * A178941 A178155 A026396` `Adjacent sequences: A033486 A033487 A033488 * A033490 A033491 A033492`
	KEYWORD	`nonn`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com).`
	EXTENSIONS	`Better description and more terms from Benoit Cloitre (benoit7848c(AT)orange.fr), Jan 06 2004`

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Last modified February 15 12:25 EST 2012. Contains 205786 sequences.