OFFSET
1,1
COMMENTS
LINKS
FORMULA
For n>1 a(n) = 1-floor(1/A001222(n)). - Enrique Pérez Herrero, Aug 08 2012
Dirichlet g.f.: Sum_{n>=1} a(n)/n^s = Zeta(s)-1-P(s), where P is prime zeta. - Enrique Pérez Herrero, Aug 08 2012
a(n) = 1 if A001222(n) > 1, 0 otherwise. - Antti Karttunen, Nov 20 2017
MATHEMATICA
A066247[n_]:=1-Boole[PrimeQ[n]]-KroneckerDelta[n, 1] (* Enrique Pérez Herrero, Oct 13 2010 *)
Table[Boole[CompositeQ[n]], {n, 1, 105}] (* Jean-François Alcover, Jan 25 2018 *)
PROG
(PARI) a(n)=!isprime(n)&&n>1 \\ Charles R Greathouse IV, Aug 21 2011
(Haskell)
a066247 1 = 0
a066247 n = 1 - a010051 n -- Reinhard Zumkeller, Feb 04 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, Dec 09 2001
STATUS
approved