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A010057 a(n) = 1 if n is a cube, else 0. 72
1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Multiplicative with a(p^e) = 1 if 3 divides e, 0 otherwise. - Mitch Harris, Jun 09 2005

a(A000578(n)) = 1; a(A007412(n)) = 0. - Reinhard Zumkeller, Oct 22 2011

a(n) = A000007(sum(A010872(A124010(n,k))): k = 1..A001221(n)) for n > 0. - Reinhard Zumkeller, Jun 21 2013

If n has 4 divisors, a(n) = bigomega(n) - 2. - Wesley Ivan Hurt, Jun 06 2014

REFERENCES

E. Landau, Elementary Number Theory, translation by Jacob E. Goodman of Elementare Zahlentheorie (Vol. I_1 (1927) of Vorlesungen ueber Zahlentheorie), by Edmund Landau, with added exercises by Paul T. Bateman and E. E. Kohlbecker, Chelsea Publishing Co., New York, 1958, pp. 31-32.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Index entries for characteristic functions

FORMULA

Dirichlet generating function: zeta(3s). - Franklin T. Adams-Watters, Sep 11 2005

a(n) = f(n,0) with f(x,y) = if x>0 then f(x-3*y*(y+1),y+1) else 0^(-x). - Reinhard Zumkeller, Sep 27 2008

a(n) = 1 + floor(n^(1/3)) - ceiling(n^(1/3)). - Wesley Ivan Hurt, Jun 06 2014

a(n) = floor(n^(1/3)) - floor((n-1)^(1/3)). - Mikael Aaltonen, Feb 24 2015

MAPLE

A010057 := proc(n)

    if isA000578(n) then # implemented in A000578

        1;

    else

        0;

    end if;

end proc: # R. J. Mathar, May 28 2016

MATHEMATICA

Table[ Boole[ IntegerQ[n^(1/3)]], {n, 0, 80}] (* Jean-François Alcover, Jun 10 2013 *)

PROG

(Haskell)

a010057 0 = 1

a010057 n = fromEnum $ all ((== 0) . (`mod` 3)) $ a124010_row n

a010057_list = concatMap (\x -> 1 : replicate (a003215 x - 1) 0) [0..]

-- Reinhard Zumkeller, Jun 21 2013, Oct 22 2011

(PARI) a(n) = ispower(n, 3); \\ Michel Marcus, Feb 24 2015

(Python)

from sympy import integer_nthroot

def A010057(n): return int(integer_nthroot(n, 3)[1]) # Chai Wah Wu, Apr 02 2021

CROSSREFS

Cf. A000578.

Cf. A003215. - Reinhard Zumkeller, Sep 27 2008

Sequence in context: A281815 A205988 A167700 * A204220 A281814 A279484

Adjacent sequences:  A010054 A010055 A010056 * A010058 A010059 A010060

KEYWORD

nonn,easy,mult

AUTHOR

N. J. A. Sloane, Mar 15 1996

STATUS

approved

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Last modified December 1 05:20 EST 2021. Contains 349426 sequences. (Running on oeis4.)