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A068905 Binomial(sigma(n),omega(n)), where sigma(n) is the sum of divisors of n (A000203) and omega the number of distinct prime factors (A001221). 3
1, 3, 4, 7, 6, 66, 8, 15, 13, 153, 12, 378, 14, 276, 276, 31, 18, 741, 20, 861, 496, 630, 24, 1770, 31, 861, 40, 1540, 30, 59640, 32, 63, 1128, 1431, 1128, 4095, 38, 1770, 1540, 4005, 42, 142880, 44, 3486, 3003, 2556, 48, 7626 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
MATHEMATICA
Binomial[DivisorSigma[1, #], Length[FactorInteger[#]]]&/@Range[50] (* Harvey P. Dale, Feb 18 2011 *)
PROG
(PARI) a(n)=binomial(sigma(n), omega(n)) \\ Charles R Greathouse IV, Feb 19 2013
CROSSREFS
Sequence in context: A334127 A095001 A344458 * A241625 A081826 A021746
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Mar 06 2002
STATUS
approved

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Last modified June 20 18:51 EDT 2024. Contains 373532 sequences. (Running on oeis4.)