A066090 a(n) = binomial(sigma(n), n).

1, 3, 4, 35, 6, 924, 8, 6435, 715, 43758, 12, 30421755, 14, 1961256, 1307504, 300540195, 18, 62359143990, 20, 513791607420, 129024480, 3796297200, 24, 36052387482172425, 736281, 166509721602, 12033222880, 7648690600760440, 30

Offset

1,2

Links

Harry J. Smith, Table of n, a(n) for n=1..200

Example

a(4) = binomial(sigma(4),4) = binomial(7,4) = 7!/(4!3!) = 35.

Mathematica

Table[ Binomial[ DivisorSigma[1, n], n], {n, 1, 32} ]

Prog

(PARI) { for (n=1, 200, a=binomial(sigma(n), n); write("b066090.txt", n, " ", a) ) } \\ Harry J. Smith, Nov 12 2009

Crossrefs

Cf. A066449, A064366.

Sequence in context: A025140 A246015 A078504 * A251259 A042891 A032835

Adjacent sequences: A066087 A066088 A066089 * A066091 A066092 A066093

Keyword

easy,nonn

Author

Joseph L. Pe, Dec 30 2001

Extensions

Corrected and extended by Robert G. Wilson v, Dec 31 2001

Status

approved