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

1,2

Links

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

Mathematica

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

Prog

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

Crossrefs

Cf. A068905, A068903, A204292.

Sequence in context: A249875 A308557 A134748 * A309774 A244296 A143046

Adjacent sequences: A068901 A068902 A068903 * A068905 A068906 A068907

Keyword

nonn

Author

Reinhard Zumkeller, Mar 06 2002

Extensions

More terms from Carl Najafi, Oct 10 2011

Status

approved