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A141241
a(n) = number of divisors of n-th positive integer with a nonprime number of divisors. a(n) = the number of divisors of A139118(n).
1
1, 4, 4, 4, 6, 4, 4, 6, 6, 4, 4, 8, 4, 4, 6, 8, 6, 4, 4, 4, 9, 4, 4, 8, 8, 6, 6, 4, 10, 6, 4, 6, 8, 4, 8, 4, 4, 12, 4, 6, 4, 8, 6, 4, 8, 12, 4, 6, 6, 4, 8, 10, 4, 12, 4, 4, 4, 8, 12, 4, 6, 4, 4, 4, 12, 6, 6, 9, 8, 8, 8, 4, 12, 8, 4, 10, 8, 4, 6, 6, 4, 4, 16, 4, 4, 6, 4, 12, 8, 4, 8, 12, 4, 4, 8, 8, 8, 12, 4
OFFSET
1,2
COMMENTS
a(1) = 1 and all other terms are composite, of course.
MATHEMATICA
Select[DivisorSigma[0, Range[200]], !PrimeQ[#]&] (* Harvey P. Dale, Mar 20 2015 *)
PROG
(PARI) for(i=1, 200, if(!isprime(numdiv(i)), print1(numdiv(i)", "))) \\ Franklin T. Adams-Watters, Apr 09 2009
CROSSREFS
Sequence in context: A164821 A348677 A130331 * A140696 A160401 A114742
KEYWORD
nonn
AUTHOR
Leroy Quet, Jun 16 2008
EXTENSIONS
More terms from Franklin T. Adams-Watters, Apr 09 2009
STATUS
approved