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A033489 a(1) = 1, a(n) = 2*a(n-1) + a([n/2]). 1
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; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..30.

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.

EXTENSIONS

Better description and more terms from Benoit Cloitre, Jan 06 2004

STATUS

approved

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Last modified September 20 18:26 EDT 2018. Contains 315240 sequences. (Running on oeis4.)