A068903 -id:A068903 - cp's OEIS frontend

A068904 a(n) = binomial(sigma(n),tau(n)), where sigma(n) is the sum and tau(n) the number of divisors of n (A000203, A000005).

1, 3, 6, 35, 15, 495, 28, 1365, 286, 3060, 66, 376740, 91, 10626, 10626, 169911, 153, 3262623, 190, 5245786, 35960, 58905, 276, 2558620845, 4495, 111930, 91390, 32468436, 435, 11969016345, 496, 67945521, 194580, 316251, 194580, 783768050065, 703, 487635

Offset: 1

Reinhard Zumkeller, Mar 06 2002

nonn

Alois P. Heinz, Table of n, a(n) for n = 1..10000 (first 1024 terms from Antti Karttunen)

Cf. A068905, A068903, A204292.

Table[Binomial[DivisorSigma[1, n], DivisorSigma[0, n]], {n, 50}] (* Carl Najafi, Oct 10 2011 *)

a(n)=binomial(sigma(n),numdiv(n)) \\ Charles R Greathouse IV, Feb 19 2013

More terms from Carl Najafi, Oct 10 2011

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).

Original entry on oeis.org

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

Offset: 1

Reinhard Zumkeller, Mar 06 2002

nonn

G. C. Greubel, Table of n, a(n) for n = 1..1000

Cf. A068903, A068904.

Binomial[DivisorSigma[1,#],Length[FactorInteger[#]]]&/@Range[50]  (* Harvey P. Dale, Feb 18 2011 *)

a(n)=binomial(sigma(n),omega(n)) \\ Charles R Greathouse IV, Feb 19 2013

cp's OEIS Frontend

A068904 a(n) = binomial(sigma(n),tau(n)), where sigma(n) is the sum and tau(n) the number of divisors of n (A000203, A000005).

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