A033497 - OEIS

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A033497

a(1) = 1, a(2) = 2, a(3) = 4, otherwise a(n) = 2a(n-1) + a(floor(n/2)).

1, 2, 4, 10, 22, 48, 100, 210, 430, 882, 1786, 3620, 7288, 14676, 29452, 59114, 118438, 237306, 475042, 950966, 1902814, 3807414, 7616614, 15236848, 30477316, 60961920, 121931128, 243876932, 487768540 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	MAPLE	`A033497 := proc(n) option remember; if n <= 3 then 2^(n-1) else A033497(n-1)+A033497(round(2*(n-1)/2))+A033497(round((n-1)/2)); fi; end;`
	PROG	`(PARI) a=vector(99, i, i(i-1)/2+1); for(n=4, #a, a[n]=2a[n-1]+a[n\2]); a \\ Charles R Greathouse IV, Nov 29 2011`
	CROSSREFS	`Sequence in context: A091618 A181158 A018108 * A192627 A075560 A078040` `Adjacent sequences: A033494 A033495 A033496 * A033498 A033499 A033500`
	KEYWORD	`nonn,easy`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com).`

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Last modified February 15 18:22 EST 2012. Contains 205835 sequences.