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A135937 a(1)=1; for n>=2, a(n) = product{d|a(n-1)} (d+1), where the product is over all positive divisors d of a(n-1). 1
1, 2, 6, 168, 6623019333730800000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The next term is a lot bigger than 70000! and is too large to include. - Stefan Steinerberger, Dec 31 2007

LINKS

Table of n, a(n) for n=1..5.

EXAMPLE

The positive divisors of a(3)=6 are 1,2,3,6. So a(4) = (1+1)*(2+1)*(3+1)*(6+1) = 2*3*4*7 = 168.

MATHEMATICA

a = {1}; Do[AppendTo[a, Times @@ (Divisors[a[[ -1]]] + 1)], {4}]; a (* Stefan Steinerberger, Dec 31 2007 *)

CROSSREFS

Cf. A135938.

Sequence in context: A281819 A199482 A168649 * A182523 A137532 A072116

Adjacent sequences:  A135934 A135935 A135936 * A135938 A135939 A135940

KEYWORD

nonn

AUTHOR

Leroy Quet, Dec 07 2007

EXTENSIONS

a(5) from Stefan Steinerberger, Dec 31 2007

STATUS

approved

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Last modified October 18 02:23 EDT 2019. Contains 328135 sequences. (Running on oeis4.)