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A107078 Whether n has non-unitary prime divisors. 10
0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Also the characteristic function of the numbers that are not squarefree: A013929. - Enrique Pérez Herrero, Jul 08 2012

The sequence of partial sums of this sequence is A057627. - Jason Kimberley, Feb 01 2017

LINKS

Enrique Pérez Herrero, Table of n, a(n) for n = 1..5000

Index entries for characteristic functions

FORMULA

a(n) = 1 if A056170(n)>0, 0 otherwise.

a(n) = A107079(n) - A013928(n+1).

a(n) = 1 - A008966(n). - Reinhard Zumkeller, Oct 03 2008

a(n) = Sum_{k=0..n-1} (mu(n-k-1) mod 2) - Sum_{k=0..n-1} (mu(n-k) mod 2).

a(n) = abs(mu(n) - (-1)^omega(n)) = (mu(n) - (-1)^omega(n))^2 = abs(A008683(n) - (-1)^A001221(n)). - Enrique Pérez Herrero, Apr 28 2012

a(n) = 1 - mu(n)^2. - Enrique Pérez Herrero, Jul 08 2012

MATHEMATICA

Table[1-MoebiusMu[n]^2, {n, 1, 100}] (* Enrique Pérez Herrero, Jul 08 2012 *)

CROSSREFS

Cf. A087049. - R. J. Mathar, Aug 24 2008 Cf. A013929, A008683, A008966, A107078.

Sequence in context: A160351 A023969 A060039 * A163533 A020987 A072786

Adjacent sequences:  A107075 A107076 A107077 * A107079 A107080 A107081

KEYWORD

easy,nonn

AUTHOR

Paul Barry, May 10 2005

STATUS

approved

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Last modified November 23 19:08 EST 2017. Contains 295128 sequences.