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A007731 a(n)=a([ n/2 ])+a([ n/3 ])+a([ n/6 ]). 8
1, 3, 5, 7, 9, 9, 15, 15, 17, 19, 19, 19, 29, 29, 29, 29, 31, 31, 41, 41, 41, 41, 41, 41, 55, 55, 55, 57, 57, 57, 57, 57, 59, 59, 59, 59, 85, 85, 85, 85, 85, 85, 85, 85, 85, 85, 85, 85, 103, 103, 103, 103, 103, 103, 117, 117 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

T. D. Noe, Table of n, a(n) for n=0..10000

P. Erdos, A. Hildebrand, A. Odlyzko, P. Pudaite and B. Reznick, The asymptotic behavior of a family of sequences, Pacific J. Math., 126 (1987), pp. 227-241.

FORMULA

From given link, a(n) is asymptotic to c*n where c = 12/log(432) = 1.97744865.. - Benoit Cloitre, Dec 18 2002

MAPLE

A007731 := proc(n) option remember; if n=0 then RETURN(1) else RETURN( A007731(trunc(n/2))+A007731(trunc(n/3))+A007731(trunc(n/6))); fi; end;

MATHEMATICA

a[n_] := a[n] = a[Floor[n/2]] + a[Floor[n/3]] + a[Floor[n/6]] ; a[0] = 1; Table[a[n], {n, 0, 60}] (* Jean-Fran├žois Alcover, Mar 06 2014 *)

PROG

(Haskell)

a007731 n = a007731_list !! n

a007731_list = 1 : (zipWith3 (\u v w -> u + v + w)

   (map (a007731 . (`div` 2)) [1..])

   (map (a007731 . (`div` 3)) [1..])

   (map (a007731 . (`div` 6)) [1..]))

-- Reinhard Zumkeller, Jan 11 2014

CROSSREFS

Cf. A083662, A088468, A165704, A165706. - Reinhard Zumkeller, Sep 26 2009

Cf. A061984.

Sequence in context: A217250 A213923 A218452 * A079377 A047747 A007957

Adjacent sequences:  A007728 A007729 A007730 * A007732 A007733 A007734

KEYWORD

nonn,easy,nice

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified April 23 22:11 EDT 2014. Contains 240947 sequences.