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A035004 Number of divisors of the n-th nonprime. 10
1, 3, 4, 4, 3, 4, 6, 4, 4, 5, 6, 6, 4, 4, 8, 3, 4, 4, 6, 8, 6, 4, 4, 4, 9, 4, 4, 8, 8, 6, 6, 4, 10, 3, 6, 4, 6, 8, 4, 8, 4, 4, 12, 4, 6, 7, 4, 8, 6, 4, 8, 12, 4, 6, 6, 4, 8, 10, 5, 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, 3, 4, 4, 6, 4, 12, 8, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
a(n+1) = a(n) only when a(n) is even. Will these repeat terms include each even integer >= 4? (See also A075036.) - Bill McEachen, Nov 16 2021
LINKS
FORMULA
a(n) = A000005(A018252(n)). - Omar E. Pol, Jan 31 2013
MATHEMATICA
DivisorSigma[0, Select[Range[200], !PrimeQ[#]&]] (* Harvey P. Dale, Mar 07 2016 *)
PROG
(PARI) for(n=1, 33, if(!isprime(n), print1(numdiv(n), ", "))) \\ edited by Michel Marcus, Jan 04 2016
CROSSREFS
Sequence in context: A253718 A350188 A295570 * A222290 A222430 A222275
KEYWORD
easy,nonn
AUTHOR
Jason Earls, Jul 05 2001
EXTENSIONS
More terms from Lior Manor, Aug 16 2001
STATUS
approved

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Last modified April 14 03:22 EDT 2024. Contains 371652 sequences. (Running on oeis4.)